need help please

I tried online calculators. I don't understand it. it is division I guess to find the value of x but I cant figure it out.
6x2 + 9x when 5=x don't know how to find the value of x
3x
 
reeses4601 said:
yes the second problem is what I ment to post.
Click to expand...

When they say "evaluate when x = 5", you are to substitute 5 in for x in the expression.

Thus, if I said evaluate 2x² -3x when x = 4, you would do: 2(4)² - 3(4) = 2(16) - 12 = 32 - 12 = 20.

Make sense?

Now you try with your expression.
 
Reeses,

Now that we the problem you want to solve - what have you tried?!

Please share your work with us.

You need to read the rules of this forum. Please read the post titled "Read before Posting" at the following URL:

http://www.freemathhelp.com/forum/th...217#post322217

We can help - we only help after you have shown your work - or ask a specific question (e.g. "are these correct?")
 
Reeses, do you understand that this requires only two things:
1) That you know what "x= 5" means and
2) that you be able to do the arithmetic.

"x= 5" simply means that you replace x with the number "5" and do the arithmetic: can you calculate "2x+ 3" if x= 5?
(I see that this was exactly what srmichael told you in post #5.)
 
I came up with that earlier and I did replace the x with 5 and I did come up with 2x+3 and every answer I got was wrong. This is why im so confused. All the rules that I know is wrong. Maybe im not simplifying it right. I divided I tried multiplying nothing makes sence.
 
HallsofIvy said:
Reeses, do you understand that this requires only two things:
1) That you know what "x= 5" means and
2) that you be able to do the arithmetic.

"x= 5" simply means that you replace x with the number "5" and do the arithmetic: can you calculate "2x+ 3" if x= 5?
(I see that this was exactly what srmichael told you in post #5.)
Click to expand...
Yes this was my first answer then I added and got 5 but it was wrong. Im confused. I found an example and I cant figure out how they got the answer
 
reeses4601 said:
I did replace the x with 5 and I did come up with 2x+3
Click to expand...
If you "replaced the x with 5", then the x should be gone, having been replaced. How did you then "come up with 2x + 3"?

Please show your work, so we can see what you're doing. Thank you. ;)
 
Find the value of the expression when x=5 6x^2+9x/3x

hi i think your asking the value of that expression when x=5

you already know the x value, so substitute that value in the given expression

if you directly substitute x value, then you get the answer 13

Given expression (6x2+9x)/3x
so take 3x common in numerator
[3x(2x+3)]/3x
now cancel the 3x in both numerator and the denominator
the expression left was 2x+3
now substitute the x value in the expression
2(5)+3=13:eek:
 
Yes, tutor, that is exactly what everyone has been telling Reeses4601 from the first response. He keeps telling us he DID that, got "5" and that was the wrong answer. But he refuses to show exactly HOW he got "5" or how he knows that is the wrong answer.
 
You must log in or register to reply here.
Top