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