Question

The 1/2 part really confuses me because you have to multiply something and i can't think of the number

Answer 1

there is a few ways to do this, lets try solving for the variable first.
1/2x+13>20
first subtract 13 on BOTH sides to try and isolate x
1/2x>7
now we will multiply by 2 because we are trying to get rid of the 1/2
x>14
any number, not including, 14 will work. It seems that we are left D as the answer because it has to be higher than 14, not equal to.