7X-20=540和4.2乘2.3-2x=3.5
问题描述:
7X-20=540和4.2乘2.3-2x=3.5
答
7X-20=540
7X=540+20
7X=560
X=80
2.3-2X=3.5
-2X=3.5-2.3
-2X=1.2
-X=0.6
X=-0.6