Liam is solving the equation 7x+6(x+3)=83

Question

. His steps are shown below. What mistake did Liam make while solving?

7x+6(x+3)=83
7x+6x+3=83
13x+3=83
13x+3−3=83−3
13x=80
13x/13= 80/13
x=6 2/13

Answer 1

Liam made a mistake when he combined 7x and 6(x+3). The correct way to do it would be 7x+6(x+3)=83 should be expanded to 7x+6x+18=83, not 7x+6x+3=83. Liam forgot to distribute the 6 to both the x and the 3.