Question

-frac7{12}+frac7{12}

Answer 1

You left the {} out for the 7's
\[-\frac{7}{12}+\frac{7}{12}\]

Answer 2

Or is it something else?

Answer 3

If it's ^that then the answer is 0. If it's something different then the answer is probably something else....

Answer 4

its right

Answer 5

phi thats correct

Answer 6

3x+(8y)+10x+4x

Answer 7

17x+8y

Answer 8

You should post new questions as a separate question.
But to answer, if you have 3 x's and 10 x's you have 13 x's
but you can't mix apples and oranges , or in this case x and y

Answer 9

it a case of x and y

Answer 10

-frac1{9}{(-9x) ??

Answer 11

\[new ? 12(y-2)-3(7-3y)\]

Answer 12

@phi that was input wrong

Answer 13

Here's a short video that might help
http://www.khanacademy.org/video/solving-equations-with-the-distributive-property?playlist=Algebra+I+Worked+Examples
He has lots more.

Answer 14

thank you