17/20
you want to get the bottom numbers the same by multiplying:)
5x4= 20 , 4x5= 20
since you multiplied the fraction with the denominator 5 by 4 , you also multiply the number on top by 4
3x4= 12
and since the other fraction with the denominator 4 was multiplied by 5 , you multiply the number on top by 5
1x5= 5
now you add those 2 numbers up
5+12= 17
you put that number on top of the fraction: 17
and take the number you ————
got from the first step and
put it on the bottom: 20
and you get 17/20 or .85