已知A=2x+4y—2,B=-2x+y+3,则3A—4B=?
已知集合A={Y|Y=X^2-4X+3},B={Y|Y=-X^2-2X+2}则A∩B=
若向量x,y满足3x+4y=a,2x+3y=b,a,b为已知向量,则x=?,y=?
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:A=X*X-3xy+y*y,B=2x*x+xy-3y*3y.求A+B,A-B,A+2B
已知集合A={(x,y)| (y-3)/ (x-1)=2,x,y∈R},B={(x,y)| 4x+ay=16,x,y∈
已知A=2x—4y,B=—2x²+6x—3(y—x),求:3A-B;
已知集合A={(x,y)|2x+3y=6},B={(x,y)|x-2y=-4},求A∩B,
已知3x+2y=a,2x+3y=b,则(x+y)(x-y)=?
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
1)已知4X=5y,求(X+y):y 2)已知(a-b):(a+b)=3:7,求a:b
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=2x-4y,B=-2x的2次方+6x-3{y-x},求:{1}2A-B{2}3A-B