解方程 x+10=23（检验） 1/5x+5=35 递等式计算（2/15+7/12）*3-3/20

x + 10 = 23
解 x = 20 - 10
x = 13
检验：把x = 13代入方程,左边 ＝ 13 + 10 ＝ 23 右边＝ 23
所以,x = 13 是方程 x + 10 = 23的解
1/5 x + 5 = 35
解 1/5 x = 35 - 5
1/5 x = 30
x = 30×5 ＝ 150
检验：把x = 150代入原方程得 左边＝1/5 ×150 + 5 = 35 右边 ＝ 35
所以,x = 150是方程 1/5 x + 5 = 35的解
（2/15 + 7/ 12)* 3 - 3/20
= 2/15 ×3 + 7/12 ×3 - 3/20
= 2/5 + 7/4 - 3/20
= 8/20 + 35/20 - 3/20
= (8 + 35 - 3)/20
= 40/20
= 2