Question

1) Rezolvati ecuatia( x+2)^2-(x-3)^2=25
2)Aratati ca (x-1)(x^2-1)-4(x+1)=(x+1)^2(x-3)

Answer 1

1) 
( x+2)^2-(x-3)^2=25
=>  x^2 + 4x + 4 - (x^2 -6x + 9) = 25
=> x^2 + 4x + 4 - x^2 + 6x - 9 = 25
=> 10x - 5 = 25
=> 10x = 30
=> x = 3

2)
(x-1)(x^2-1)-4(x+1)=(x+1)^2(x-3)
=> x^3 - x - x^2 +1 - 4x - 4 = (x^2 + 2x + 1)(x-3)
=> x^3 - x^2 -5x - 3 = x^3 + 2x ^2 + x - 3x^2 - 6x - 3
=> x^3 - x^2 -5x - 3 =  x^3 - x^2 -5x - 3 
=> is egale