Question

Please help Explanation will be appreciated thanks,

Answer 1

Answer: A; 6.3%

Explanation:

Problem 1

For the first problem, we first want to find y so that we can plug it into the expression.

We can use elimination method for the system of equations to solve.

3x+3y=21

3x-y=5

We subtract both equations to eliminate x.

4y=16 [divide both sides by 4]

y=4

Now that we know y, we can plug it into the expression.

`(4)/(2) -3` [divide]

`2-3` [subtract]

`-1`

We know that the answer is A.

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Problem 2

For the second problem, we need to know how to calculate percent error. The formula for precent error is
`(|measured-exact|)/(exact) *100%`. We know that the exact value is 80 because the buyer was supposed to given 80. 75 is the measured value because that was what the buyer was given.

`(|75-80|)/(80) *100%` [subtract]

`(|-5|)/(80) *100%` [solve absolue value]

`(5)/(80) *100%` [divide]

`0.0625*100%` [multiply]

`6.25`

Since the problem said to round to one decimal place, we know that the answer is 6.3%.