(1+20%)X=(1-10%)Y.
[(2x+3y)²-(y+2x)(2x-y)-10y(x+y+1)÷2y其中x=2019,y=20
y=ln(1+x),求y^10(x)?
1/(x+y)-1/(x+y)=3/20 2/(x+y)+3/(x-y)=19/20 这是
集合N={(x,y)|(x-1)^2}+(y-1)^20},M={(x,y)|x^2+y^2
用加减法解方程组:{(x+y)/6+(x-y)/10=3 (x+y)/6+(y-x)/10=-1
解方程组x+y/6+x-y/10=3,x+y/6+y-x/10=-1
已知:x-y=1,x+y=-7,求代数式3(x+y)+20(x-y)-5的值
化简求值:(x+y)-(2x+1/2y)-(3x+1/6y)-(4x+1/12y)-(5x+1/20y)-.(10x+1
{ x-y/7-x+y/10=1/2 {2(x-y)+5(x+y)=3
解方程组:(x+3)(y-2)=(x-3)(y+10),(x+1)(y+3)=(x-2)(y+12)
10/x+y+3/x-y=-5 15/x+y-2/x-y=-1(用换元法解此方程组)
已知x y为实数,且(x+y)(x+y+1)=20 求x+y的值