To answer this question you must make a come factor between the 2 fractions I believe the easiest way to do this is multiply the denominator or bottom number by the other one so 4*5 and 5*4 and what you do to the denominator you must do to the numerator so you would have to do 4*4 and 4*5 for the first fraction to get 16/20 and repeat on the other side 1*5 and 4*5 or 5/20 so the to fractions are 16/20+5/20 then add just the numerators 16+5=21 or 21/20 and simplify to 1/20
You have the same graph instead you write y in place of x. The horizontal one is y axis and vice versa. This is done mostly for reversed functions. like x^2 function and √x
