## Algebra 1: Common Core (15th Edition)

The distributive property allows us to distribute anything multiplied by something inside of the parenthesis to whatever is inside of the parenthesis. Thus, we distribute the 7 to everything inside the parenthesis, giving us $21x-28=49.$ We now need to get the x alone. Thus, we cancel out the subtraction by adding 28 on both sides. Finally, we use division, so we divide both sides by 21 to isolate x.