We're given the hypotenuse and one side and we're looking for the missing side so use pythagorean.
20² - 16² = 144²
Square root of 144 = 12 feet
Answer:
25a^2-49
Step-by-step explanation:
1)use FOIL
F=first
O=out
I=inside
L=last
5a*5a+5a*-7+7*5a*7*-7
25a^2-35a+35a-49
25a^2-49
Hope this helps!