(((12х+3)-5х)-2х)+10х=54
((12х+3-5х)-2х)+10х=54 (12х+3-5х-2х)+10х=54 12х+3-5х-2х+10х=54 15х=41 х=41/15 х=2 11/15
(((12х+3)-5х)-2х)+10х=54 12х+3-5х-2х+10х=54 15х=51 х=51/15 х=3,4