化简：5 * 7y

化简：5 * 7y 化简:3(x-y)²-7(x-y)+ 2(x-y)²+5(x-y) （7y-3z)-(8y-5z)=?化简! (7Y-3Z)-(8Y-5Z)化简 化简2（2X-7Y)(7Y+2X)+X^2-(-4X+5Y)(-5Y-4X) 把(x-y)看作一个整体,化简:(1)5(x-y)+2(x-y)-4(x-y);(2)3(x-y²-4(x-y)+7（x-y)-6(x-y) 化简{21x^5y^7-28x^7y^4+7y(2x^3y^2)^2}/(-7x^5y^4) 化简[21x^5y^7-28x^7y^4＋7y(2x³y²)²]÷(-7x^5y^4） 2(y-4)(3y+2)-5(-3y+7)(y+1),其中y=-1 化简3(x-y)-7(x--y)+2(y-x) 化简 (一7y)+12y一8y 化简:5(x-y)+2(x+y)-3(x-y) 7y-10y+5=4y-5 5分之7y等于y+1 y是多少 5分之7y=y+1 y是多少啊 3(y-3)-5(1+y)=7(y-1) 5(y-2)-7(y+3)=11(y+4) 10y+7=22y-5-3y 10y+7=22y-5-3y