Simplifying an algebraic expression by rewriting it in a more usable form is one of the most frequently used skills in algebra. You will study two others – solving an equation and sketching the graph of an equation – later in this text. To simplifying an algebraic expression generally means to remove symbols of grouping and combine like terms. For  instance, the expression x + (3 + x) can be simplified as 2x + 3.

Simplify each expression.

a. -3(- 5x)    b. 7 ( – x)

Solution

a. -3(- 5x)  = (- 3)( – 5)x
= 15x

b. 7( – x) = 7(- 1)(x)
= -7x