70%X+20%X=3.
(x-22)+(x-24)+(x-27)+(x-20)=x
x-(20%*X +20%*X+50)=70怎么解?
(70-X )x 20=400 方程
(x+2005)/ (x+2004)+(x+2007)/(x+2006)=(x+2008)/(x+2007)+(x+20
(X+X)+(X-X)+(X*X)+(X/X)=100
X+13%X-28%X=3.
0.88(X+20%X)=X+84
20*X+30*3X+70*(50-X-3X)=1800
(20-2x)(20-2x)x>400 x=?
(X+X*20%)-[(1200-X)-(1200-X)*20%]=40%
X+X*20%-(1200-X)-(1200-X)*20%=40%
x-30%x=14x+25%x=20