12) 7 + 7x
7(x + 1/7)
For the second equation, use the distributive property.
7x + 7 * 1/7
7x + 1
7 + 7x and 7(x + 1/7) are not equivalent expressions.
13) 2.5(3 + x)
2.5x + 7.5
Again, use the distributive property for the first equation
2.5x + 2.5*3
2.5x + 7.5
2.5(3 + x) and 2.5x + 7.5 are equivalent expressions.