am i just plain stupid?

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The formula is d=rt. You have d=3. That is, the plane is flying 3 miles. You have the rates, times and distances. Put them in the formula and solve for the two variables.
 
Denis said:
sportsstar469 said:
an airplane takes 3 hours to travel a distance of 2160 miles with the wind. The return trip takes 4 hours against the wind. find the speed of the plane in still air and the speed of the wind.
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C'mon SStar, slow down; you're complicating something real easy;
the net speeds are this easy to get:
with wind: 2160 / 3 = 720 mph ; so plane's real speed is slower than that
against wind: 2160 / 4 = 540 mph ; so plane's real speed is faster than that...get my drift?
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lol i see what you did there no pun intended with drift? =p
yeah i see what you mean. since distance equals rate times time and im looking for the rate or speed of the planes. divining the distance by the time should give it to me. sthe problem asked to build two linear equations though and if i recall correctly they took
3(x+y)=2160
4(x-y)=2160
where x is plane speed and y is wind (they used r and w)
so you get 3x+3y=2160
and or 4x-4y=2160
which simplifies to x+y=720
x-y=540
this leads to my question. i am supposed to enter this into my calculator and solve either graphically or numerically. i have no idea how to enter this. i usually have equations with one variable so i can enter them into y1 or y2 etc. this has 2 variables. i tried solving for y but thay just makes them horizontal lines at 720 and 540 when ienter them into my calculators.
 
sportsstar469 said:
Denis said:
sportsstar469 said:
an airplane takes 3 hours to travel a distance of 2160 miles with the wind. The return trip takes 4 hours against the wind. find the speed of the plane in still air and the speed of the wind.
Click to expand...
C'mon SStar, slow down; you're complicating something real easy;
the net speeds are this easy to get:
with wind: 2160 / 3 = 720 mph ; so plane's real speed is slower than that
against wind: 2160 / 4 = 540 mph ; so plane's real speed is faster than that...get my drift?
Click to expand...
lol i see what you did there no pun intended with drift? =p
yeah i see what you mean. since distance equals rate times time and im looking for the rate or speed of the planes. divining the distance by the time should give it to me. sthe problem asked to build two linear equations though and if i recall correctly they took
3(x+y)=2160
4(x-y)=2160
where x is plane speed and y is wind (they used r and w)
so you get 3x+3y=2160
and or 4x-4y=2160
which simplifies to x+y=720
x-y=540
this leads to my question. i am supposed to enter this into my calculator and solve either graphically or numerically. i have no idea how to enter this. i usually have equations with one variable so i can enter them into y1 or y2 etc. this has 2 variables. i tried solving for y but thay just makes them horizontal lines at 720 and 540 when ienter them into my calculators.
Click to expand...

x + y = 720 ..................................(1)
x - y = 540...................................(2)

If you add the two equations you get:

(x+ y) + (x - y) = 1260

2x = 1260

x = 630

y = x - 540 = 90

Now you should check this answer by plugging these back into (1) and (2) and verify.
 
yeah i know how to solve it symbollically but i need to plug the two equations into my calculator and solve graphically. im not sure how to enter them i usually have equations like 2x-3=3 and that i can plug into y sub 1 but idk how to plug in x+y=720.
i changed them to y=mx plus b form but the graph looked wrong compared to hers!
 
Then you won't know what you're doing...so I guess you could become a teacher :D
 
lool. well anyway i thought id tell you guys that i got a 19/20 on my quiz. i have my big test tomorrow. im still pretty confused on ANYTHING with graphs, and the systems word problems are kind of confusing as well. i am determined to get an A in this course and keep my 4.0 gpa atleast until fall semester (september) where i hope i can get a B in trig, b in chem 101 and An A in advanced bio. my tutor says im not confident enough in myself and i know all of this. she made a joke ill be an engineer lol.
 
Denis said:
Then you won't know what you're doing...so I guess you could become a teacher :D
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hey denis yo uare the one that said he helped a d student get a b from just correcting his carelessness right? what exactly helped him not be so carelss. i can go through a whole problem and get all of the algebra correct but get the problem wrong because ithought that 5 plus 3 equals 7.
 
sportsstar469 said:
Denis said:
Then you won't know what you're doing...so I guess you could become a teacher :D
Click to expand...
hey denis yo uare the one that said he helped a d student get a b from just correcting his carelessness, right? what exactly helped him not be so carelss. i can go through a whole problem and get all of the algebra correct but get the problem wrong because ithought that 5 plus 3 equals 7.
Click to expand...

By getting him to read over his own creation.
 
well yeah i know i was careless there.
i took my big chapters 1-3 test today and let me tell you i think i got a 95-100 easily. i found it to ber so easy. everyone else in the class was really struggling though. im concerned about logarithms. i know the basics of logs from watching youtube videos like log2 of 8=3 or log8 of 16= 4/3 but idk if ill be able to solve the equations.
good thing is from looking at the youtube videos im going into the lessons with some gun fire. e havent even started logarithms
 
You do know that logs are basically a tool to solve for the "power" variable, do you?

Like, 3^p = 81 : solve for p
And p = log(81) / log(3)

...something to keep at the back of your mind...if there is room back there !
 
you calling em stupid ;( lol jk.
so how would i solve for p? divide by 3?

so it would be
27=log3of 81?
i did know that logs were just trying to find the power of soemthing but you made it easy to understand. i havent ever learned logs befgore and we're not doing them for a few weeks but i just reviewed them last summer to make sure id do well in this class. its just all the equations look harder than what im discussing now with you. and the number e or naturall ogs seems complicated as well.
 
sportsstar469 said:
so how would i solve for p? divide by 3?
so it would be
27=log3of 81?
Click to expand...
NO!
get log(81) ; use your calculator; you'll get 4.3944491.... ; log(3) = 1.0986122...
divide them: 4.3944491 / 1.0986122 = 4
3^4 = 81 ; kapish?
 
idk denis the log equations look REALLY CONFUSING they ar elike raised to an exponent and that same exponent minus x. its really confusing.

BUT i have a question for you guys that i hiope you can answer.
ok so im factoring trinomials. and its easy for me as im sure it is for you guys as well. anyways heres the problem... -2xsquared-5x+3
so anyway i did factoring by grouping and i got
-1(2x-1)(x+3)
anyway my teacher says that if i factored outt he neg 1 first (like i did) then when i get to the end i multiply one side by neg 1.
so if i have -1(2x-1)(x+3)
i changed that to (1-2x) (x+3)<-this is my final answer!!!
the book has (3+x)(1-2x) as their final answer
are they the same?
also inotice they dont have two possible answers. do i have to multiply a certain side by -1 or would both have been acceptable?
 
sportsstar469 said:
2xsquared-5x+3
the book has (3+x)(1-2x) as their final answer
Click to expand...
Star, PLEASE start using ^ (the power sign): 2x^2 - 5x + 3

If the book has correct answer, then expression you typed is incorrect;
should be: 2x^2 + 5x - 3

The factoring for the expression you typed is: (x - 1)(2x -3)

I suggest you use Google:
http://www.google.ca/search?hl=en&q=int ... =&aq=f&oq=

AND next time you post a NEW problem, please start a NEW thread: you were told that before.

Here's how/what factoring expression "gets going":
some teacher wrote down 2 bracketed terms at random, like (x - 2)(2x + 5);
he then multiplied them out:
(x - 2) times (2x + 5)
= x(2x +5) -2(2x + 5)
= 2x^2 + 5x - 4x - 10
= 2x^2 + x - 10

He then gives you 2x^2 + x - 10 and says: factor that, suckah!
Your job is to find what he started with: (x - 2)(2x + 5); kapish ?
 
This has grown old. I am locking the topic. Please begin new threads for new problems.
 
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