Name: Evaluating expressions: solution walkthrough
Uploaded: 2026-11-13
Duration: 1 min 30 s
Description: If a = -4 and b = 5, what is the value of a² + 3a - b? Try it, then watch the animated solution.

Replace each letter with its value, inside parentheses:

({-4})^2 + 3({-4}) - 5

.

({-4})^2

means

({-4})({-4})

. A negative times a negative is positive, so it equals

16

.

Next multiply:

3({-4}) = {-12}

. The expression is now

16 - 12 - 5

.

Work from left to right:

16 - 12 = 4

, then

4 - 5 = {-1}

.

Traps:

{-33}

squares to

{-16}

,

23

makes

3({-4})

positive, and

9

adds

b

instead of subtracting it.

Try it first