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:
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 .
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 :
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.
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https://brainly.com/question/1957976