Question

Explain and correct the error made by a student who simplified this expression.

Equation: –2x + 7x + 8
What the student did:
–2x + 7x + 8
(–2 + 7 + 8)x
13x

Answer 1

5x + 8

Explanation:

- 2x + 7x + 8

the student has added the numerical values of the 3 terms even though they are not all like terms

correction

- 2x + 7x + 8 ← collect like terms

(- 2x + 7x) + 8

= 5x + 8

Answer 2

Hello,

That is (+8) and not (+8x) at the end

Correct the error :

`- 2x + 7x + 8`

`= x( - 2 + 7) + 8`

`= 5 * x + 8`

`= 5x + 8`