(х+1)*(x²-10х+25)=7(х-5)

(х+1)*(x²-10х+25) = 7(х-5),
(х+1)(х-5)² = 7(х-5),
(x+1)*(x-5)²-7(x-5) = 0,
(x-5)*((x+1)*(x-5)-7) = 0,

x-5 = 0,
x₁ = 5,

(x+1)*(x-5)-7 = 0,
x²-5x+х-5-7 = 0,
x²-4x-12 = 0,  
D = (-4)² - 4*1*(-12) = 16 + 48 = 64,
x₂ = (4 + 8)/2*1 = 12/2 = 6,   
x₃ = (4 - 8)/2*1 = -4/2 = -2.

Ответ: x₁ = 5   x₂ = 6   x₃ = -2.