Question

Which method will NOT solve this equation completely?

-8 + 3y = 19

○Add 8 to both sides, then divide both sides by 3.
○Divide both sides by 3,then add 8/3 to both sides
○Add 8 to both sides, then multiply both sides by 1/3
○Subtract 8 from both sides, then divide both sides by
1/3
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Answer 1

○ Subtract 8 from both sides, then divide both sides by 1/3

Explanation:

Perhaps the usual sequence of steps is ...

add 8:

3y = 27

divide by 3 (equivalently, multiply by 1/3)

y = 9

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If the division by 3 is done first, then the constant on the left becomes -8/3, so cancelling it requires adding 8/3 to both sides of the equation.

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If you do the last suggestion, you get ...

subtract 8 from both sides:

-16 +3y = 11

divide both sides by 1/3:

-48 +9y = 33 . . . . . . . does not solve the equation completely