Answer:
x=5 and x=-11
Step-by-step explanation:
(x-2)(x+8)=39

Subtract 39 from both sides

Factor:
(x-5)(x+11)=0
Set factors to 0.
x-5 =0
x+11 =0
x=5, x=-11
Answer:
V = 540 inches ^3
Step-by-step explanation:
The area of the base is found be finding the other leg
a^2 +b^2 = c^2
12^2+b^2 = 15^2
144 +b^2 = 225
b^2 = 225-144
b^2=81
Take the square root of each side
b = 9
We can find the area of the triangle
B = 1/2 (9*12)
B =54
The Volume is given by
V = Bh
V = 54*10
V = 540 inches ^3
Answer: 18
Proof:
Step 1: Add what's in the parentheses - (4+1) = 5
Step 2: Subtract 5 - 2 and multiply that by the sum of the parentheses - 5-2 = 3(5) = 15
Step 3: Add 3 - 15 + 3 = 18