Question

1. evaluate the expression $5x - 20$ when

a) $x = 3$
b) $x = -3$

Explanation:

Part (a)

Step1: Substitute \( x = 3 \) into the expression

Substitute \( x = 3 \) into \( 5x - 20 \), we get \( 5\times3 - 20 \).

Step2: Calculate the result

First, calculate \( 5\times3 = 15 \), then \( 15 - 20 = -5 \).

Step1: Substitute \( x = -3 \) into the expression

Substitute \( x = -3 \) into \( 5x - 20 \), we get \( 5\times(-3) - 20 \).

Step2: Calculate the result

First, calculate \( 5\times(-3)= -15 \), then \( -15 - 20 = -35 \).

Answer:

\( -5 \)

Part (b)