Question

Gabriel used the expression 2.5x + 2y – 2 to represent his total cost, and 28 – 2.5x – 2y to represent the amount of change he should receive from $30. What was Gabriel’s error?

Answer 1

Answer:

He should add 2 in 30 but he subtracted 2 from 30                                                      

Step-by-step explanation:

The total cost : $2.5x + 2y - 2$

Now he gave $ 30

So, amount change he received:

= $30 - (2.5x + 2y - 2)$

= $30 - 2.5x - 2y +2$ --b

= $32 - 2.5x - 2y$  

While we are given that he should receive : $28 -2.5x -2y$

So, the Gabriel's error was in b

He should add 2 in 30 but he subtracted 2 from 30

In b he applies the property of signs incorrectly

(-) * (-) = (+) but he applied (-) * (-) = (-)

By applying wrong property he got the -2 while we applied the correct property we got +2

So, this was the error .                                                                                                                 

Answer 2

Gabriel subtracts 2 instead of adding 2 hence, the mistake is in the 2nd step and this is determined by using the arithmetic operations.

Given :

• Gabriel used the expression (2.5x + 2y – 2) to represent his total cost.
• (28 – 2.5x – 2y) to represent the amount of change he should receive from $30.

The amount of change he should receive from $30 will be:

$=30-(2.5x+2y-2)$

$=-2.5x-2y+2+30$

$=-2.5x-2y+32$

So, Gabriel subtracts 2 instead of adding 2 hence, the mistake is in the 2nd step.

For more information, refer to the link given below:

https://brainly.com/question/1957976