Question

x+12=7x-6
15-x=4x
Va rog

Answer 1

x+12=7x-6
x-7x=-6-12
-6x=-18
x=-18:(-6)
x=3

15-x=4x
-x-4x=-15
-5x=-15
x=-15:(-5)
x=3

Answer 2

$\displaystyle a).x+12=7x-6 \\ x-7x=-6-12 \\ -6x=-18 \\ x= \frac{-18}{-6} \\ x=3$
$\displaystyle b).15-x=4x \\ -x-4x=-15 \\ -5x=-15 \\ x= \frac{-15}{-5} \\ x=3$