Exercise 20 Page 149

We are given an expression and asked to evaluate it for some given values. x=1.8, 5, 6.4This means that we should substitute 1.8, 5, and 6.4 for x in the given expression and then evaluate. Let's start with 1.8.

2x +3.1

Substitute

x= 1.8

2( 1.8)+3.1

Multiply

Multiply

3.6+3.1

AddTerms

Add terms

3.7

Now, let's do the same thing for the rest of the values.

x	Evaluation	Result
1.8	2( 1.8)+3.1	3.7
5	2( 5)+3.1	13.1
6.4	2( 6.4)+3.1	15.9