1/9y=-2
I see that the answer is -18 but I don't really understand the formula to get the answer. 1/9y=-2
I see that the answer is -18 but I don't really understand the formula to get the answer. @Mathematics

Question

amistre64 · Answer

there is no formula, there is just algebra

amistre64 · Answer

how do we get y all alone?  how do we undo a 1/9 ?

amistre64 · Answer

this is a concept known as inverses, how to undo what was done prior

anonymous · Answer

thanks Amistre64...  I am trying to teach this to my daughter. I can do it in my head but I am having a hard time explaining how I got the answer.

amistre64 · Answer

yeah, its the inverse concept that they are working on.  The inverse to left is right, top is bottom, addition is subtraction, division is multiplication.

multiply both sides by 9 to undo the division by 9

amistre64 · Answer

$$\frac{1}{9}y=-2$$
$$(9)\frac{1}{9}y=-2(9)$$
$$y=-18$$

anonymous · Answer

very well stated. thank you very much.

amistre64 · Answer

your welcome, and good luck with it all ;)

preetha · Answer

My son had a problem with this concept in algebra as wll.  So it really helped to see the same operation performed on both sides, then written out and then simplified.  good job amistre.