90-X=(180-X)2/3-40解此方程,过程!

问题描述:

90-X=(180-X)2/3-40解此方程,过程!

90-X=(180-X)2/3-40
90-x=120-2x/3-40
1/3x=10
x=30

90-X=(180-X)2/3-40
两边乘以3;270-3x=360-2x-120
-3x+2x=240-270
-x=-30
x=30