Answer the question....

Dear Student,
Solution) Given: x = 1 and y = 6
Put these values in
8x - ay + a² = 0
8 - 6a + a² = 0
a² - 6a + 8 = 0
Splitting middle term,
a² - 4a - 2a + 8 = 0
a(a - 4) - 2(a - 4) = 0
(a - 2) (a - 4) = 0
a = 2, 4 
Regards!