Question

Как решить уравнение х+20=40

Answer 1

х+20=40
х=40-20
х=20
20+20=40

Answer 2

x+20=40
x=40-20
x=20
---------------------------------
20+20=40
40=40

Answer 3

x+20=40
x=40-20
x=20
--------------------------------
20+20=40
40=40