X+X20%-(1200-X)-(1200-X)20%=40%

来源：学生作业帮编辑：搜搜考试网作业帮分类：数学作业时间：2024/04/30 03:51:22

X+X*20%-(1200-X)-(1200-X)*20%=40%

X+X*20%-(1200-X)-(1200-X)*20%=40% ,等式左右同时乘以100得
100X+X*20-100*(1200-X)-(1200-X)*20=40
120X-(1200-X)*120=40
12X-(1200-X)*12=4
3X-(1200-X)*3=1
3X-3600+X*3=1
6*X=3601
X=3601/6 ,约等于600

(X+X*20%)-[(1200-X)-(1200-X)*20%]=40% X+X*20%-(1200-X)-(1200-X)*20%=40% (20+2x)(40-x)=1200 (40-x)(20+2x)=1200 (40-x)(20+2x)=1200 800+80X-20X-2x^2=1200 -2x^2+60X-400=0 x^2 (x-22)+(x-24)+(x-27)+(x-20)=x (x+2005)/ (x+2004)+(x+2007)/(x+2006)=(x+2008)/(x+2007)+(x+20 0.88（X+20%X)=X+84 ((20＋2X)(40-x)==1200求解 (40-x)(20+8*x/4)=1200 (20+2x)(40-x)=1200,怎样解, （40-x）（20+2x）=1200