3x^2+11x+10因式分解(x^2+3x+2)(x^2+7+12)-120 5x^2-6xy-8y^2

问题描述:

3x^2+11x+10因式分解
(x^2+3x+2)(x^2+7+12)-120
5x^2-6xy-8y^2

3x^2+11x+10=(3x+5)(x+2)(x^2+3x+2)(x^2+7+12)-120 =(x+1)(x+2)(x+3)(x+4)-120=(X^2+5x+4)(x^2+5x+6)-120=(X^2+5x+4)^2+2(X^2+5x+4)-120=(X^2+5x+4+12)(X^2+5x+4-10)=(X^2+5x+16)(X^2+5x-6)=(x-1)(x+6)(X^2+5x...