# Factor (x^2+y)^2-10(x^2+y)+16

(x2+y)2-10(x2+y)+16
Let u=x2+y. Substitute u for all occurrences of x2+y.
u2-10u+16
Factor u2-10u+16 using the AC method.
Consider the form x2+bx+c. Find a pair of integers whose product is c and whose sum is b. In this case, whose product is 16 and whose sum is -10.
-8,-2
Write the factored form using these integers.
(u-8)(u-2)
(u-8)(u-2)
Replace all occurrences of u with x2+y.
(x2+y-8)(x2+y-2)
Factor (x^2+y)^2-10(x^2+y)+16