Answer:
a. To find the volume when the width is 5 inches, we plug in w=5 into the equation:
V = 2w³ - 7w² + 3w
V = 2(5)³ - 7(5)² + 3(5)
V = 250 - 175 + 15
V = 90
Therefore, the volume is 90 cubic inches.
b. To factor the polynomial, we can first factor out a w:
V = w(2w² - 7w + 3)
Then we can factor the quadratic expression in parentheses:
V = w(2w - 1)(w - 3)
Each factor represents a dimension of the rectangular prism:
w is the width
2w - 1 is the length
w - 3 is the height
c. If the width is 5 inches, we can use the factorization from part b to find the other dimensions:
length = 2w - 1 = 2(5) - 1 = 9 inches
height = w - 3 = 5 - 3 = 2 inches
This means that the rectangular prism has dimensions 5 inches by 9 inches by 2 inches. We can also use the dimensions to calculate the volume:
V = 5 × 9 × 2 = 90 cubic inches
This is the same as the answer from part a.
d. The graph of the polynomial is:
Graph of the polynomial
The x-intercepts are approximately 0.5 and 3. These correspond to the widths at which the volume is 0, which means the rectangular prism has zero volume. In other words, the x-intercepts represent the points where the rectangular prism collapses into a flat shape.
e. The domain of the function is all real numbers, since we can plug in any width w and get a corresponding volume. The range of the function is also all real numbers, since the volume can be any positive or negative value depending on the width. Specifically, the range is (-∞, ∞).