Question

Розкласти на множники: 1)x²-25; 2)x²+4x+4; 3)x³-25x; 4)x²-y²+x+y.

Answer 1

Відповідь:

1) x²-25 = (x-5)(x+5)

2) x²+4x+4 = x²+2·2+2² = (x+2)²

3) x³-25x = x(x²-25) = x(x-5)(x+5)

4) x²-y²+x+y = (x+y)(x-y)+x+y = (x+y)(x-y)+(x+y) = (x+y)((x-y)+1) = (x+y)(x-y+1).