Question

12a+16=160
2x+15=-x+60
esses?

Answer 1

12a + 16 = 160
12a = 160 - 16
12a = 144
a = 144
    -------- 
      12

a = 12


2x + 15 = -x + 60
2x + x = 60 - 15
3x = 45 
x = 45
     -----
       3
x = 15

Answer 2

Olá vamos lá!

$12a + 16 = 160$
$12a = 160 - 16$
$a = 144 / 12$
$a = 12$

2x + 15 = -x + 60
2x + x = 60 - 15
x = 45 / 3
x = 15

qualquer duvida, comente ;)
Bons estudos!