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

3a. $4(2y+1)=2(y-13)$ Expand: $8y+4=2y-26$ Subtract 4 from both sides: $8y+4-4=2y-26-4$ Simplify: $8y=2y-30$ Subtract 2y from both sides: $8y-2y=2y-30-2y$ Simplify: $6y=-30$ Divide both sides by 6: $\frac{6y}{6}=\frac{-30}{6}$ Simplify: $y=-5$ 3b. $7(4-a)=3(a-4)$ Expand: $28-7a=3a-12$ Subtract: $-7a=3a-40$ Subtract 3a froom both sides: $-7a-3a=3a-40-3a$ Simplify: $-10a=-40$ Divide both sides by -10: $\frac{-10a}{-10}=\frac{-40}{-10}$ Simplify: $a=4$