3y 5 7y 4 (- y 1 ) 5 July 8, 2019 16 32 64 128 3y 5 7y 4 (- y 1 )+ 5 3 - 7y 5y - 3 4) 4 + (7y - 3)/5 (3y + 5)/4 - (3y)/2 5-y/4 = 3/7
