please help

[rgeer]

Hello,

Im am completly stuck on some problems, May I please have help, I would be so greatful even if u can just get me at least started.

1)multiple choice: Which line passes through the point (2,-1)?
a)2y-x=0 b)2x-y=0 c)3x-2y=8 d)3x+2y=8

2)Find the unknown coordinate of the point on the line x-2y=8, when x=6.

3)Find the unknow coordinate of the point on the line 3y-1=x,when x=-3.

4)Does (2,-2) pass through the equation 4x+y=10?

5)Does (3,10) pass through the equation y=-2x+4?

Thanks in advance again,
Ryan

 

[stapel]

1) Plug x = 2, y = -1 into each line equation. Which one "works"? (That is, which one results in a true statement?)

2) Plug "6" in for "x". Solve for "y".

3) Plug "-3" in for "x". Solve for "y".

4) Plug x = 2, y = -2 into the equation. Does it "work"?

5) Plug x = 3, y = 10 into the equation. Does it "work"?

Eliz.

 

[rgeer]

1) Plug x = 2, y = -1 into each line equation. Which one "works"? (That is, which one results in a true statement?)

2) Plug "6" in for "x". Solve for "y".

3) Plug "-3" in for "x". Solve for "y".

4) Plug x = 2, y = -2 into the equation. Does it "work"?

5) Plug x = 3, y = 10 into the equation. Does it "work"?

Eliz.

1)C is the one that works, thanks for the help.

2)when I solve I get -2y=2, so is that the answer?

3)when i solve I get 3y=2, is this the answer?

4)I get -2=2, is this the answer?, if so wouldnt it be true, yes it does work.

5)I get 6=6 when i solve, is this the answer?

Thanks,
please reply
Ryan

 

[stapel]

2) Now solve for the value of y.

3) Now solve for the value of y.

4) How do you get that -2 is equal to +2?

5) The question is "is this point on the line?", not "does six equal six?" I told you how to check if the point is on the line. You need to answer "yes" or "no".

Eliz.

 

[jsbeckton]

you need to divide both sides by the constants to solve for the variables in 2&3

-2y=2 which is true but its not solved for y
it should be y=-1 after you divide both sides by -2

watch your signs on 4&5 your problem is in the arithmitic, and if the statement is true eg: 5=5 then the point is on the line, it satisfies the equation.

Thats what a line is, a collection of points that satisfy the equation. When your calculator plots the line, it just plots all of the points that "work" and the end result is a line.