<u>Answer</u>
D.25x2 – 36
<u>Explanation</u>
A. x² – 16x + 64
product = 64
sum = -16
factors: -8 and -8
x² – 16x + 64 = x² - 8x - 8x + 64
= x(x - 8) - 8(x - 8)
= (x - 8)(x-8) = (x-8)² ⇒ Not a difference of squares
B.x² + 4 = (x² + 2²) ⇒ Not a difference of squares
C.9x² – x – 36
product = - 324
sum = -1
Factors: none
9x² – x – 36 ⇒ Has no perfect roots.
D.25x² – 36
25x² – 36 = (5x)² - 6² ⇒ This is the difference of squares.
The relationship of the angles to the sides opposite those angles is always:
30°=1, 60°=√3, and 90°=2
So the longer leg can be found using the ratios from above...
L/S=√3/1 and we are told that the shorter side is 5 in so
L/5=√3
L=5√3
So A. is the correct answer.
