First option because 3 x 10^9 is 3,000,000,000
Combine like terms to get 2x + 6x which is 8x and 3y + 9y which is 12y so the simplified answer is 8x + 12y
Im pretty sure the answer id b
Hi there!
Let's solve this equation step by step!

First add 7 to both sides.

Next we need to take a look at the meaning of the stripes between our variable. Those stripes mean we are dealing with an absolute value function. The absolute value stripes make everything between the stripes positive; also when we plug in a number. In this particular question we can plug in both -13 and 13 at the position of n, because when -13 is made positive, it fulfils the equation.
Hence,

or

~ Hope this helps you!