Two pairs of glass for $x = 2x
money paid after discount = (1 - 0.25) x ( 2x)
= 0.75(2x)
6 jackets cost = 6y
money paid after discount ( 1 - 0.25) x (6x) = 0.75(6y)
Total amount Adam paid = 0.75(2x) + 0.75(6y)
factor 0.75 out
Total amount Adam paid = 0.75( 2x + 6y)