91.2*(21+X)=92*21+90.5*X怎么求
问题描述:
91.2*(21+X)=92*21+90.5*X怎么求
答
91.2*21+91.2X=92*21+90.5X
91.2X-90.5X=92*21-91.2*21
(91.2-90.5)X=(92-91.2)*21
0.7X=0.8*21
X=24
答
91.2x+1915.2=1932+90.5x
91.2x-90.5x=1932-1915.2
0.7x=16.8
x=24