Answers

2015-07-19T14:23:46+08:00

This Is a Certified Answer

×
Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
We subtract 7x from both sides so that the RHS would be 0.
x² - 7x - 18 = 0

We look for two numbers with a product of 18 and a difference of 7.
18 - 1 = 17  X
9 - 2 = 7  √
6 - 3 = 3  X 

So,
(x-9)(x+2)=0
This would mean that x=9 or x =-2 since one of thee factors need to be 0. (in order to know this, equate both factors to 0.)

Check:
If x = 9
9² - 7(9) - 18 = 0
81 - 63 - 18 = 0
18 - 18 = 0
0 = 0  This is indeed TRUE

If x = -2
(-2)² - 7(-2) -18 = 0
4 + 14 - 18 = 0
18 - 18 = 0
0 = 0  This indeed TRUE
1 5 1
how about the chhecking..im just curios