Answer:
67p + 35
Explanation:
Reduce all the unnecessary plus and minus signs. A plus and negative sign equates to just a minus sign.
4p + -7(-5 + -9p) = 4p - 7(-5 - 9p)
Expand the variables in the brackets. These take priority over regular evaluation of the other signs. Two negative values multiplied together produces a positive product.
4p - 7(-5 - 9p) = 4p + 35 + 63p
Add all like products together.
4p + 35 + 63p = 67p + 35
Check that the final simplification can no longer be simplified.