x:y=3, rest 53 =>3y+53=x sau 3y-x=-53 sau x-3y=53 sau 6x-18y=318
a)6x-18y+25 devine 318+25=343=7³, ceea ce era de demonstrat
b)Pentru x+y=269 =>x=269-y
(269-y)/y=3, rest 53 =>269-y=3y+53 =>269-53=4y =>216=4y =>y=54
x=269-54 =>x=215
Deci avem {215, 54} solutii maxime.