因式分解法计算:(1) -7ab-14abx+49aby; (2) (x-1)^3y^3+(1-x)^3z^3;(3)(x^2+x)^2 -3(x^2+x)+2; (4) x^2-y^2-z^2+2yz;(5)3x^2+2xy-8y^2; (6) x^2-x-30; (7) x^4+4.
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因式分解法计算:(1) -7ab-14abx+49aby; (2) (x-1)^3y^3+(1-x)^3z^3;(3)(x^2+x)^2 -3(x^2+x)+2; (4) x^2-y^2-z^2+2yz;(5)3x^2+2xy-8y^2; (6) x^2-x-30; (7) x^4+4.
因式分解法计算:
(1) -7ab-14abx+49aby; (2) (x-1)^3y^3+(1-x)^3z^3;
(3)(x^2+x)^2 -3(x^2+x)+2; (4) x^2-y^2-z^2+2yz;
(5)3x^2+2xy-8y^2; (6) x^2-x-30; (7) x^4+4.
因式分解法计算:(1) -7ab-14abx+49aby; (2) (x-1)^3y^3+(1-x)^3z^3;(3)(x^2+x)^2 -3(x^2+x)+2; (4) x^2-y^2-z^2+2yz;(5)3x^2+2xy-8y^2; (6) x^2-x-30; (7) x^4+4.
(1) -7ab-14abx+49aby;
= -7ab(1+2x-7y)
(2) (x-1)^3y^3+(1-x)^3z^3
=(x-1)³(y³-z³)=(x-1)³(y-z)(y²+yz+z²)
(3)(x^2+x)^2 -3(x^2+x)+2;
=(x²+x-1)(x²+x-2)=(x²+x-1)(x-1)(x-2)
(4) x^2-y^2-z^2+2yz;
=x²-(y-z)²
=(x-y+z)(x+y-z)
(5)3x^2+2xy-8y^2;
=(3x-4y)(x+2y)
(6) x^2-x-30;
=(x-6)(x+5)
(7) x^4+4.
=(x²+2)²-4x²
=(x²+2-2x)(x²+2+2x)