[75%x- (x-90)]×10=[(x-70)-(x-90)]×15
问题描述：
[75%x- (x-90)]×10=[(x-70)-(x-90)]×15
答
第一种[75%x- (x-90)]×10=[(x-70)-(x-90)]×15
(0.75x-x+90)*10=(x-70-x+90)*15
(90-0.25x)*10=20*15
90-0.25x=30
0.25x=90-30=60
x=240 第二组 [75%x-(x-90)]×10=[(x-70)-(x-90)]×15
7.5x-10-900=15x-1050-15x-1350
7.5x=15x-1050-15x-1350+910
7.5x=15x-1050-15x-440
x=240
答
[75%x-(x-90)]×10=[(x-70)-(x-90)]×15
7.5x-10-900=15x-1050-15x-1350
7.5x=15x-1050-15x-1350+910
7.5x=15x-1050-15x-440
x=240
答
[75%x- (x-90)]×10=[(x-70)-(x-90)]×15
(0.75x-x+90)*10=(x-70-x+90)*15
(90-0.25x)*10=20*15
90-0.25x=30
0.25x=90-30=60
x=240