Hi there!
Recall the volume of a pyramid is:
V = 1/3(bh)
We are given the volume and side length of the base. Find the area of the base:
A = s²
A = (5xy²)² = 25x²y⁴
Plug in the solved for base:
125x³y³ = 1/3(25x²y⁴)h
To isolate for h, begin by multiplying both sides by 3:
375x³y³ = (25x²y⁴)h
Divide both sides by 25x²y⁴. Use the following exponent property:
xᵃ / xᵇ = xᵃ⁻ᵇ
Thus:
375x³y³ / 25x²4⁴ = 15x/y.
The height must be equal to:
Answer:
b.
Step-by-step explanation:
We have to look at sign changes in f(x) to determine the possible positive real roots.
There is only one sign change here, between the -8x and the +4. So that means there is only 1 possible real positive root.
Now we have to look at sign changes in f(-x) to determine the possible negative real roots.
There are 3 sign changes here. That means there are either 3 negative roots or 3-2 = 1 negative root. So we have:
1 positive
3 or 1 negative
We need to pair them up now with all the possible combinations.
If we have 1 positive and 1 negative, we have to have 2 imaginary
If we have 1 positive and 3 negative, we have to have 0 imaginary
Keep in mind that the total number or roots--positive, negative, imaginary--have to add up to equal the degree of the polynomial. This is a 4th degree polynomial, so we will have 4 roots.