In the perfect square trinomial: x² + 10x + c, c = 25
Proof:
Plug in 25 for c. Find factors of x and 25 that, when added will give you 10x
x² + 10x + 25
x 5
x 5
(x + 5)(x + 5)
Use the FOIL method to check:
x(x) = x² , x(5) = 5x, 5(x) = 5x, 5(5) = 25
x² + 5x + 5x + 25: simplify: x² + 10x + 25
25 is your value
hope this helps