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

The entire expression should be subtracted from 30. To subtract the quantity, distribute the negative sign, which changes the signs on the terms. So, the –2 changes to positive and gets added to 30 instead of subtracted from it.

Hope this helps! ^^

Answer 2

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 .