Question

7x+7=2(x+1) comprobacion

Answer 1

7x+7=2(x+1)
7x + 7 = 2x + 2
7x - 2x = 2 - 7
5x = - 5
x = - 5/5
x = - 1

Comprobamos.
7x + 7 = 2 (x + 1)
7 (- 1) + 7 = 2 (- 1 + 1)
- 7 + 7 = - 2 + 2
0 = 0

Listo, es correcto. 

Answer 2

Resolver.

7x + 7 = 2(x + 1)
7x + 7 = 2x + 2
7x - 2x = 2 - 7
5x = - 5
x = -5/5
x = - 1

Comprobación.

7x + 7 = 2(x + 1)
7(- 1) + 7 = 2( - 1 + 1)
- 7 +  7    = 2(0)
   0          =  0