I need to find x by factoring but I was absent the day we reviewed and forgot from last year: the question is: If x^2+3x = 9x -8 what is the value of x?

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asked Feb 5, 2019 229k views

1 Answer

Mansoor Akram · Answer 1 · 2019-02-10T19:30:53+0000

x²+3x = 9x - 8

Subtract 9x on both sides

x² - 6x = -8

Add 8 on both sides

x² - 6x + 8 = 0

Now you need to find the factors of 8(numbers that multiply to equal 8) that add or subtract to -6.

Factors of 8: 1, 2, 4, 8

2 and 4 add up to 6, if they are both negative they equal -6.

(x - 2)(x - 4) = 0

x - 2 = 0

x = 2

x - 4 = 0

x = 4

x = 2, x = 4