What’s the answer
Apparently didn’t paid attention in class

This equation can be written as :-

= 6 + 4x = x + 15

= 4x+6=x+15

= 4x + 6 − x = x + 15 − x

= 3x + 6 = 15

= 3x + 6 − 6 = 15 − 6

= 3x = 9

= 3 x 3 = 9

= x = 9 ÷ 3

= x = 3

Using this , let us solve the equation :-

= 6 + 4 × 3 = 3 + 15

= 6 + 12 = 3 + 15

= 18 = 18

Therefore , 6 + 4x = x + 15 = 18 ( x = 3 ) .