作业帮计算(3x-4)(x 2)-(x 5)(x-3)
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/22 01:17:19
原式=[3x-4x2+2x3-2x2]÷（-2x）=（2x3-6x2+3x）÷（-2x）=-x2+3x-32．
1/(x-3)-6/(x2-9)-(x-1)/(6+2x)=1/(x-3)-6/[(x+3)(x-3)]-(x-1)/[2(x+3)]=[2x+6-6*2-(x-1)*(x-3)]/[2(x+3)(x
（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．
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(x^2+2x+4)(x^2+2x-3)-8设m=x^2+2x+4原式=m(m-7)-8=m^2-7m-8=(m+1)(m-8)=(x^2+2x+4+1)(x^2+2x+4-8)=(x^2+2x+5)
lim(x²-9)/(x²-2x-3)x趋近于3=lim(x+3)(x-3)/(x+1)(x-3)x趋近于3=lim(x+3)/(x+1)x趋近于3=(3+3)/(3+1)=3/2
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
原式=(x^2-1)(x^2+2)=x^4+x^2-2
原式=-x+2x2+5+4x2-3-6x=6x2-7x+2．
原式=3x2-[7x-4x+3-2x2]=3x2-7x+4x-3+2x2=5x2-3x-3
原式=[x+2x(x-2)-x-1(x-2)2]÷x2-16x2+4x=[x2-4x(x-2)2-x2-xx(x-2)2]÷x2-16x2+4x=x-4x(x-2)2•x(x+4)(x+4)(x-4)
12.5x(4x2.5)+(12.5x0.8)x2.5=125+25=150
(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-
原式=5x²-x²-(4x-x²)+2(x²-3x)=4x²-4x+x²+2x²-6x=7x²-10x
M={x|x(x-2)>0}={x|x2}N={x|(x-1)(x-3)
(5x²+3x-4)-(2x²+x+5)+(2x²-x+5)=5x²+3x-4-2x²-x-5+2x²-x+5=5x²+x-4
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)]=