Разложите на множители:
1) $7a^2 - 7$;
2) $3b^3 - 3b$;
3) $2x^3 - 2xy^2$;
4) $-8a^5 + 8a^3 - 2a$;
5) $x - 4y + x^2 - 16y^2$;
6) $ab^6 - ab^4 - b^6 + b^4$.
$7a^2 - 7 = 7(a^2 - 1) = 7(a - 1)(a + 1)$
$3b^3 - 3b = 3b(b^2 - 1) = 3b(b - 1)(b + 1)$
$2x^3 - 2xy^2 = 2x(x^2 - y^2) = 2x(x - y)(x + y)$
$-8a^5 + 8a^3 - 2a = -2a(4a^4 - 4a^2 + 1) = -2a(2a^2 - 1)^2 = -2a(2a^2 - 1)(2a^2 - 1)$
$x - 4y + x^2 - 16y^2 = (x - 4y) + (x^2 - 16y^2) = (x - 4y) + (x - 4y)(x + 4y) = (x - 4y)(1 + x + 4y)$
$ab^6 - ab^4 - b^6 + b^4 = (ab^6 - ab^4) - (b^6 - b^4) = ab^4(b^2 - 1) - b^4(b^2 - 1) = (b^2 - 1)(ab^4 - b^4) = b^4(b^2 - 1)(a - 1) = b^4(b - 1)(b + 1)(a - 1)$
Пожауйста, оцените решение