Question

X^3+3x^2=25x+75 what is the solution set

Answer 1

x²(x+3) = 25(x+3)
divide both sides by (x+3)
x² = 25
subtract 25 from both sides
x² - 25
(x+5)(x-5)
x = { -5, 5 }

Answer 2

x³ + 3x² = 25x + 75
x³ + 3x² - 25x - 75 = 0

x²(x + 3) - 25(x + 3) = 0
(x² - 25) * (x + 3) = 0

(x² - 25) = 0 (x + 3) = 0
x² = 25 x = -3
x = ±5

Hope this helps! :)