计算∬(x 2)dydz zdxdy,其中Σ-搜答案-智慧作业帮

再答：满意吗，亲，别忘了给好评哦再答：0.21再问：用竖式怎样算？再答：图片中有啊再问：谢谢您再答：不客气再问：嗯

（1）原式=x(x+9)x(x+3)+(x+3)(x−3)(x+3)2=x+9x+3+x−3x+3=2(x+3)x+3=2；（2）原式=-x−2x−1÷x2−4x−1=-x−2x−1•x−1(x+2)

1/(x2-5x+6)-1/(4x-x2-3)-1/(3x-x2-2)=1/(x2-5x+6)+1/(x2-4x+3)+1/(x2-3x+2)=1/(x-2)(x-3)+1/(x-3)(x-1)+1/

原式=-x2+5+4x+5x-4+2x2=x2+9x+1．

2^5-5x2^4+10x2^3-10x2^2+5x2-1＝（2－1）^5=1再问：有过程吗再答：晕，这是二项式的展开式啊，就这样:(a+b)^n=a^n+C(n,1)a^(n-1)b+C(n,2)a

行列式展开=x1^3+x2^3+x3^3-3x1x2x3而x1^3+x2^3+x3^3-3x1x2x3=（x1+x2+x3)(x1^2+x2^2+x3^2-x1x2-x2x3-x3x1)(展开右边即得

【希望可以帮到你! 祝学习快乐! 】

5x(x2-3x-1)-x2(1-x)=5x^3-15x^2-5x-x^2+x^3=6x^3-16x^2-5x

(x²-1)/(x²-2x+1)÷(x²+x)/(x-1)=(x+1)(x-1)/(x-1)²乘(x-1)/x(x+1)=1/x

1

计算3√5X2√10

3√5×2√10=(3×2)×(√5×√10)=6×√50=6×5√2=30√2

7.5X2.3+1.9X2.5+12.5X2.5=2.5×2.3+1.9×2.5+12.5×2.5=2.5×（2.3+1.9+12.5）=2.5×16.7=10×16.7×1/4=167/4

(x/x2-9)-(1/x2+6x+9)=x/(x+3)(x-3)-1/(x+3)²=[x(x+3)-(x-3)]/(x-3)(x+3)²=[x²+3x-x+3]/(x-

题目有问题吧?168.14.再问：168.1÷（4.3x2-0.4）快点。。。。。再答：（168+0.1）÷（4*2+0.3*2-0.4）=(168+0.1)÷(8+0.2)=168÷8+168÷0.

0.3x2.5x0.4简便计算

=0.3×(2.5×0.4)=0.3×1=0.3

1.345^2-0.345x2.69+0.345^2=1.345^2-2x1.345x0.345+0.345^2=(1.345-0.345)^2=1^2=1原题少了一个平方.

80.4x2.5简便计算

80.4x2.5=(80+0.4)x2.5=80x2.5+0.4x2.5=200+1=201

由题意delta=4-4m>=0得m

原式=2x/[(x-2)(x+1)]*(x+1)/(x-1)-x(x+2)/[(x+2)(x-2)]=2x/[(x-2)(x-1)]-x/(x-2)=[2x-x(x-1)]/[(x-2)(x-1)]=