Answer: C
Step-by-step explanation:
To get all the constant terms on one side and variable terms on another, all we have to do is to add or subtract them on both sides.
3x+2x=10+5
Now that the like terms are on one side, we can combine them.
5x=15
To get x alone, we divide both sides by 5.
x=3
Now, we notice that x=3 is not an answer choice, but the next option that is equivalent to x=3 is C.
For C, if you divide both sides by -5, you still get x=3.
-15=-5x
x=3
