2a-7b=8,3a-8b-10=0 1/2x+3y=2/3,x-3/4y=-29/12

1.已知集合A=｛（x,y)|y=2x+1｝,B=｛(x,y)|y=x+3｝,a∈A,b∈B,求a 已知：A=X*X-3xy+y*y,B=2x*x+xy-3y*3y.求A+B,A-B,A+2B x+y-(2x-y)(x+y)=?12(a^2-b^2)^2-3(a^2+b^2)(a+b)^2等于多少(2a-b)(2 已知集合A={（x,y)| (y-3)/ (x-1)=2,x,y∈R},B={（x,y)| 4x+ay=16,x,y∈ 1.设A={(x,y)/4x+y=6} B={(x,y)/3x+2y=7} 则A∩B等于多少 已知:6x²-7xy-3y²+14x+y+a=(2x-3y+b)(3x+y+1)求a,b的值 已知(-2x^2y^2)(4x^ay^3)(-3x^5y^b)=24x^10y^8,求2a+3b的值 1）已知4X=5y,求（X+y)：y 2）已知（a-b）：（a+b）=3：7,求a：b 已知|x-y-3|+(a+b+4)²=0,求2a+2b-(a+b)分之（x-y）²-3（y-x)的值 3a-3b/10ab*25a^b3/a^-b^= x^-4y^/x^+2xy+y^/x+2y/2x^+2xy x²（x+y)(y-x)-xy(x+y)(x-y) 已知a+b=4,ab=-2,求多项式3a²b+3 已知集合A=｛(x,y)｜(y-3)/(x-2)=a+1｝B=｛(x,y)｜(a^2-1)x+(a-1)y=15｝,当a