Question

Gaira was asked to evaluate the algebraic expression –3.8x + 6 when x = –7.5. –3.8(–7.5) + 6(–7.5)Gaira was asked to evaluate the algebraic expression –3.8x + 6 when x = –7.5. –3.8(–7.5) + 6(–7.5) 28.5 + (–45) (–16.5) What mistake did she make 28.5 + (–45) (–16.5) What mistake did she make? What is the correct answer?

Answer 1

Gaira made a mistake when substituting the value –7.5 in for x. She multiplied both terms of the expression by –7.5 when she should have only multiplied –3.8 by –7.5. The correct answer is 34.5.

Explanation:

Did the ED2020

Answer 2

See explanation

Explanation:

Given

`x = -7.5`

`Expression: -3.8x + 6`

Required

Determine Gaira mistake

When Gaira solved the expression, she solved as:

`-3.8x + 6x`

Giving her

`-3.8x * -7.5 + 6 * -7.5`

This is incorrect as the correct expression is

`-3.8x + 6`

and it is solved as follows:

Substitute -7.5 for x in -3.8x + 6

`-3.8x + 6`

`-3.8 * -7.5 + 6`

`28.5 + 6`

`34.5`

34.5 is the correct solution