• Feb 21st 2008, 06:23 PM
megs94
I'm so confused.(Doh) How do you do these? I don't understand what to do with the number next to the x2. here's what I did. What am I doing wrong? Please help!
2x^2+10=9x
-9x -9x
2x^2=10-9x=0
-10 -10
2x^2-9x=-10
2 2
x^2-9x=-5
(x-10)(x+1)
x=-10,1
• Feb 21st 2008, 06:33 PM
mr fantastic
Quote:

Originally Posted by megs94
I'm so confused.(Doh) How do you do these? I don't understand what to do with the number next to the x2. here's what I did. What am I doing wrong? Please help!
2x^2+10=9x
-9x -9x
2x^2=10-9x=0
-10 -10
2x^2-9x=-10
2 2
x^2-9x=-5
(x-10)(x+1)
x=-10,1

I can't follow your working but I can see at least 1 mistake (you've divided some but not all terms by 2).

Re-arrange: $2x^2 - 9x + 10 = 0$

Factorise: (2x - 5)(x - 2) = 0.

Solve: x = 5/2, 2.
• Apr 28th 2008, 04:39 PM
imagxz
Theres a much easier way to do the factoring part. Cross factoring... if you can get the idea on how to do it, factoring is a breeze Read my post and comment if you'd like Factoring Quadratics for Idiots