## Evaluating Algebraic Expressions

Variables and numbers can be combined with the operations of arithmetic to produce algebraic expressions. To evaluate algebraic expressions, we substitute numbers for the variables and simplify.

**Examples** – If a = 2, b = -3 and c = -5, evaluate **a**. a + bc and **b.** (ab + 3c)/b(c – a)

**a**. **a + bc** = 2 + (-3)(-5)

= 2 + (15)

=17

**b**. **(ab + 3c)/b(c – a)** = (2(-3) + 3(-5))/-3 (-5 – 2)

= (- 6 + (-15))/-3 (-7)

= – 21/21

= -1