Question

(x+5)³-(x+1)³=4(3x²-5)решить уравнение

Answer 1

( x + 5)³ - ( x + 1)³ = 4( 3x² - 5)
x³ + 15x² + 75x + 125 - ( x³ + 3x² + 3x + 1) = 12x² - 20
x³ + 15x² + 75x + 125 - x³ - 3x² - 3x - 1 = 12x² - 20
12x² + 72x + 124 - 12x² + 20 = 0
72x = - 144
x= - 144/72
x = - 2
Ответ: x = - 2.