x-20=y+20等于几?

x-20=y+20等于几? x、y等于几 x+y=12 y+z=20 z+x=18 求X Y Z分别等于几? X+Y=90,X/Y=5,请问X等于几?Y等于几? x等于几Y等于几 x+3=5-y,那么x+y等于几 若3X=4Y,那么X;Y等于等于几比几 x乘以y等于几 X加Y等于几 (X+Y)^2等于几 X+Y等于几呵呵? x加y等于几? x和y等于几 (-x+y)(x-y)等于几 y*y*y*y+2x*x*x*x=4x*x*y 求x等于几,y等于几,写出所有选项! x+x+x=15,x+y+y=19,求y-x等于几 方程3x+7y=k与2x+5y=20的解x,y都是正数则整数k应等于几? x等于y+y+y,x+y=48,求x是几?y是几?急