Question

1. evaluate the expression $7x + 3(x - 5)$ when

a) $x = -10$
b) $x = -5$
c) $x = 5$
d) $x = 10$

Explanation:

Part (a)

Step1: Simplify the expression

First, expand and combine like terms in \(7x + 3(x - 5)\).
Using the distributive property \(a(b + c)=ab+ac\), we get:
\(7x+3x - 15\)
Combine like terms: \( (7x + 3x)-15=10x - 15\)

Step2: Substitute \(x = - 10\)

Substitute \(x=-10\) into \(10x - 15\):
\(10\times(-10)-15=-100 - 15=-115\)

Step1: Use the simplified expression

We already simplified the expression to \(10x - 15\)

Step2: Substitute \(x=-5\)

Substitute \(x = - 5\) into \(10x-15\):
\(10\times(-5)-15=-50-15=-65\)

Step1: Use the simplified expression

The simplified expression is \(10x - 15\)

Step2: Substitute \(x = 5\)

Substitute \(x = 5\) into \(10x-15\):
\(10\times5-15 = 50-15=35\)

Answer:

\(-115\)

Part (b)