(1.8*15+1*15)+(2.3*X+1*X)=58.5我是初一的,要清楚,

[(x+2)/(x+3)-(x+1)/(x+2)+(x+4)/(x+5)-(x+3)/(x+4)]/[(x的平方+7x+13)/(x的平方+8x+15)] 计算:[(x+2)/(x+3) - (x+1)/(x+2) + (x+4)/(x+5) - (x+3)/(x+4) / (x^2 + 7x + 13)/(x^2 + 8x + 15) 化简：[x+1 -(15/x-1)] * (x-4/x-1) (x-1)(x+1)(x+3)(x+5)+15 (x-1)(x+1)(x+3)(x+5)+15 2x(x-1)-x(2x-5)=15 因式分解 (x+1)(x+3)(x+5)(x+7)+15 因式分解 (x+1)(x+2)(x+5)(x+7)+15 (x+1)（x+3)(x+5)(x+7)+15因式分解 （x+1)(x+2)(x+5)(x+7)+15 因式分解 因式分解1+x+x^2+x^3+```+x^15 (x+1)(x+2)(x+3)(x+4)-15 请你说明（4x³+8x²-6x-1）+（1.5x³-4.2x²+3.7x-6）-（3.8x²-2.3x+5.5x³+15）的值与x无关 (x^21+x^15+x^12+x^9+x^6+x^3+1)/(x^2+x+1) 证明(x+1)(X+3)(x+5)(x+7)+15=(X+8x)+22(x+8x)+120 x^3+x-30(分解因式);x^12-y^12;x^15+x^14+x^13.x^2+x+1 计算1/[x(x+3)]+1/[(x+3)(x+6)]+.+1/[(x+15)(x+18)]=? 1/x(x+3)+1/(x+3)(x+6)+...+1/(x+15)(x+18)