How can i get this answer i keep getting it wrong

I got A.

X/5+a=20
First you cancel out the 5 by multiplying 5*5 so the five under the X disappears and to cancel it ou ton the other side you multiply 20*5 and that's 100.

X+a=100
Then you cancel out a.

so then you get X=100=a.

Its E because you have to convert the elements to fractions adjust the fractions based on the LCD and if the dominators are equal combine the fractions than multiply 5x2=100