Question

A student’s work is shown below.

y – 12.7 = 32.75

y – 12.7 – 12.7 = 32.75 – 12.7

y = 20.05

Which is the best statement about the student’s work?

The student solved the problem incorrectly. The student should divide both sides of the equation by -12.7 to create a zero pair.
The student solved the problem incorrectly. The student subtracted incorrectly because 32.75 – 12.7 is 20.68.
The student solved the problem incorrectly. The student should add 12.7 to both sides of the equation to isolate the variable, y.
The student solved the problem correctly. Subtracting 12.7 from both sides of the equation isolates the variable, y.

Answer 1

Answer: Choice C

The student solved the problem incorrectly. The student should add 12.7 to both sides of the equation to isolate the variable, y.

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Step-by-step explanation:

We add 12.7 to both sides to undo the "minus 12.7"

We apply the inverse operation to whatever is happening to x.

As another example, solving x-2 = 10 leads to x = 12 after adding 2 to both sides to undo the "minus 2".

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The student's steps should look like this

y - 12.7 = 32.75

y-12.7+12.7 = 32.75+12.7

y = 45.45

Notice on the left side of the second step, we have the -12.7+12.7 become 0 and go away.

Answer 2

the correct answer is

D the student solved the problem. correctly