### Home > AC > Chapter 7 > Lesson 7.2.3 > Problem7-77

7-77.

Simplify the following expressions.

1. $15x^2-3x(4+5x)$

Distribute to remove the parenthesis.
$15x^2-12x-15x^2$
$12x$

1. $\frac{1}{3}(24x-9)+10$

Follow the steps outlined in part (a).

1. $(x-3)(x+1)+2x$

Start with a generic rectangle to simplify, then use the same method as part (a).

$x^2-3$

1. $6x-2+9-3y-x$

Use the strategy shown in part (a) to solve this problem.