Answer:
20
Step-by-step explanation:
Let's start by rewriting the second equation in terms of "x":

Subtract y from both sides:

Now, substitute "5-y" for "x" in the first equation:

Note that:


Cancel out like terms:

Subtract 25 from both sides:

Divide both sides by -10

Now, substitute this value back into either of the equations to solve for x.

Add 15/2 to both sides:

Now, find the difference:

Answer:
Only b is correctly simplified.
Step-by-step explanation:
If u can’t read cause it is cut off, the top 10 is 10 and the bottom is -10.
7 is the lowest common multiple i think