Algebra Help (Part 2)

[Dillinger4]

yes it's another stupid question for all you math whizzes.

Simplifying Algebraic Expressions

1.) Clear the ()
Use the distributive property to multilpy factors in front of the ()
by every term inside and remove the ()

2.) If the sign in front of the () is + keep the sign of every term inside the () the same and remove the () if it is - then change the sign of every term inside the ().

5m^2n^3 -(6mn - 4m^2n^3 + 3) + 6

9m^2n^3 - 6mn + (-3) + 6

9m^2n^3 - 6mn + 3

The previous problem should be correct.
The next problem is correct also but where are they getting
24z^2 from in the second line? Shouldn't it be 24z?

 problem  3z^2 + 6z (-4z + 7y)

3z^2 + 24z^2 + 42yz 

(3 - 24)z^2 + 42yz 

answer -24z^2 + 42yz