5 (-3p + 7) + 5 (p - 1)

Well first u gotta simplify the equation by multiplying the outside number (the 5) into the parenthesis.

Original: 5 (-3p+7)

simplified: - 15p+35

and then you do the same for the other part.

Original: 5 (p-1)

Simplified: 5p-5

Now thats done, you now have the new equation as - 15+35+5p-5

And finally you combine like terms and your final answer should be - 10p+30

5 (-3p + 7) + 5 (p - 1) = 0

-15p + 35 + 5p - 5 = 0

-10p + 30 = 0

-10p = - 30

p = 3