几道因式分解的题目和计算题,真的很急,加分

3个回答

  • 1.6mn(3m+2n-1)

    2.原式=(x^2)^2-2x^2y^2+(y^2)^2=(X^2-Y^2)^2=(x+y)^2(x-y)^2

    3.6ab(y-x)^2〔2b+4ab+3(y-x)〕

    4.(t-7/2)^2-1/4

    5.(x-2y)(x-3y)

    6.(m+n-3)(m+n+2)

    7.(a^2+4a)^2+8(a^2+4a)+16=(a^2+4a+4)^2

    8.原式=(1000-0.2)^2=1000^2+0.2^2-2*1000*0.2=999600.04

    9.原式=(25+1/5)(25-1/5)=25^2-(1/5)^2=15624/25

    10.原式=(1+1/2)(1+1/3)……(1+1/100)(1-1/2)(1-1/3)……(1-1/100)

    =3/2*4/3*5/4……101/100*(1/2*2/3……99/100)

    =101/2*1/100

    =101/200

    1)x^2-y^2=(x+y)(x-y)=3,所以,x-y=3

    所以,4xy=(x+y)^2-(x-y)^2=-8,则xy=-2

    x^2-xy+y^2=(x-y)^2+xy=9+(-2)=7

    2)x^2+5xy+30y =x(x+5y)+30y=6x+30y=6(x+5y)=6*6=36

    3)(1+1/x)^2=25/4,所以,x^2+1/x^2=17/4

    (x-1/x)^2=x^2+1/x^2-2=9/4

    所以,x-1/x=3/2或-3/2

    x^2-1/x^2=(x+1/x)(x-1/x)=15/4或-15/4