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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

If x = -2

(-2)² - 7(-2) -18 = 0

4 + 14 - 18 = 0

18 - 18 = 0

0 = 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*