PLEASE HELP ⚠️⚠️

Elena began to solve this equation: 12x +6(4x + 3) = 6(6x + 4) - 6 12x + 24x + 18 = 36x + 24 - 6 when she got to the last line she stopped and said the equation is true for all values of x. How could Elena tell without finishing?​

MARKING BRAINLIEST IF YOU ACTUALLY TRY​