Renan found the sum (4.2x + 3) + (5.7x - 2) + (5 - 2.6x), as shown.

4.2x + 3 + 5.7x - 2 + 5 - 2.6x

4.2x + 5.7x + 2.6x + 3 - 2 + 5

(4.2 + 5.7 + 2.6) x + 3 - 2 + 5

12.5x + 6

The answer is 7.3x+6

Step-by-step explanation:

Given the expression

(4.2x + 3) + (5.7x - 2) + (5 - 2.6x),

Let us repeat the solution and compare our answer to that of Renan's to validate Renan's claims

(4.2x + 3) + (5.7x - 2) + (5 - 2.6x),

Let us open up brackets

4.2x + 3 + 5.7x - 2 + 5 - 2.6x

Collecting like terms we have

4.2x+5.7x-2.6x+3-2+5

7.3x+6

The answer is 7.3x+6

From Renan's solution in line 2 the third term is meant to be - 2.6x and not + 2.6x