化简{21x^5y^7-28x^7y^4+7y(2x^3y^2)^2}/(-7x^5y^4)
计算(x^8-x^7y+x^5y^3-x^4y^4+x^3y^5-x^y^7+y^8)(x^2+xy+y^2)
x^8-x^7y+x^6y^2-x^5y^3+x^4y^4-x^3y^5+x^2y^-xy^7+y^8
化简2(2X-7Y)(7Y+2X)+X^2-(-4X+5Y)(-5Y-4X)
化简[21x^5y^7-28x^7y^4+7y(2x³y²)²]÷(-7x^5y^4)
计算:1/(x-y)-1/(x+y)-2y/(x^2+y^2)-4y^3/(x^4+y^4)-8x^7/(x^8+y^8
(3x-4y)(5x-4y)-(7x-8y)(6y-5x)
解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7
5(2x-7y)-(4x-10y)全过程
先化简在求值 (x+5y)(x+4y)-(x-y)(x+y),其中,x=-2又2/3,y=3/7
先化简,后求值(x+5y)(x+4y)(x-y)(x+y),其中,x=-2又2/3,y=3/7
先化简,后求值(x+5y)(x+4y)(x-y)(x+y),其中,x=-2又2/3,y=3/7,用公式计算
先化简,后求值(x+5y)(x+4y)-(x-y)(x+y),其中,x等于负2又3分之2,y等于7分之3