Question

3 (x + 5) - 10 = x + 13

Answer 1

3(x+5)-10=x+13
3x+15-10=x+13
3x+5=x+13
3x-x=13-5
2x=8
x= 8 
     2
x=4

solucion:            x=4

Answer 2

3 (x + 5) - 10 = x + 13

3x + 15 - 10 = x + 13

3x - x = 13 + 10 - 15

2x = 8

x = 8/2

x = 4

Respuesta : 

x = 4