The table includes points on a quadratic function used to model the shape of a hole for one support beam at a new building site.
1 answer:
The hole is 8 feet deep at ground level ⇒ 3rd answer
Step-by-step explanation:
The form of the quadratic function is y = ax² + bx + c, where
- a is the coefficient of x²
- b is the coefficient of x
- c is the y-intercept (at x = 0)
The vertex point of the quadratic is (h , k), where
and k is the value of y when x = h
The table:
→ x : -2 , 0 , 2
→ y : -6 , -8 , -6
∵ x represents distance from hole's center in feet
∵ y represents the depth from level ground
∴ The quadratic function is y = ax² + bx + c
∵ c is the value of y at x = 0 ⇒ y-intercept
- From the table at x = 0 ⇒ y = -8
∴ c = -8
- Substitute its value in the function model
∴ y = ax² + bx - 8
- To find the values of a and b substitute x and y in the model by
the coordinates of the point in the table
∵ x = -2 and y = -6
∴ -6 = a(-2)² + b(-2) - 8
∴ -6 = 4a - 2b - 8
- Add 8 to both sides
∴ 2 = 4a - 2b
- Switch the two sides
∴ 4a - 2b = 2 ⇒ (1)
∵ x = 2 and y = -6
∴ -6 = a(2)² + b(2) - 8
∴ -6 = 4a + 2b - 8
- Add 8 to both sides
∴ 2 = 4a + 2b
- Switch the two sides
∴ 4a + 2b = 2 ⇒ (2)
Now we have a system of equation to solve it
Add equations(1) and (2) to eliminate b
∵ 8a = 4
- Divide both sides by 8
∴ a = 0.5
- Substitute value of a in equation (1) or to to find b
∵ 4(0.5) + 2b = 2
∴ 2 + 2b = 2
- Subtract 2 from both sides
∴ 2b = 0
- Divide both sides by 2
∴ b = 0
Substitute the values of a and b in the function model
∴ y = 0.5x² + (0)x - 8
∴ y = 0.5x² - 8
∵ y represents the depth from level ground
∵ The vertex of the function model is (h , k)
∴ The deep of the hole at ground level is the value of k
∵
∴
∴ h = 0
∵ k is the value of y when x = h
- From the table at x = 0 ⇒ y = -8
∴ k = -8
- Ignore the sign (-) because the k represents the depth of the
hole in feet
∴ The deep of the hole at ground level is 8 feet
The hole is 8 feet deep at ground level
Learn more:
You can learn more about the quadratic function in brainly.com/question/1332667
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Answer:
a) positive real zeros: 2 or 0; negative real zeros: 2 or 0; complex zeros: 0, 2, or 4. (rule of signs)
b) ∪-shaped, as for an even-degree polynomial with positive leading coefficient. See attached.
c, d) See attached
Step-by-step explanation:
Descarte's rule of signs gives bounds on the number of positive and negative real roots. The numbers it gives may be reduced by multiples of 2, as complex roots will come in conjugate pairs. The total number of roots of all kinds will match the degree of the polynomial.
Synthetic division is essentially polynomial long division with some modifications:
- the variables are omitted ("place value" is used instead)
- the constant in the divisor is <em>negated</em> so its product with the partial quotient can be <em>added</em> to obtain the new dividend
- the divisor binomial is assumed to have a leading coefficient of 1.
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<h3>a) </h3>The signs of the terms of the given polynomial are + - - - +. There are two sign changes, so 2 possible positive real roots.
When the signs of the odd-degree terms are changed, the signs become + + - + +. There are still two sign changes, so 2 possible negative real roots.
Either or both of these numbers can be reduced by 2 if the roots include a conjugate pair. That is, there may also be 0 possible positive real roots, and 0 possible negative real roots.
The number of non-real (complex) zeros may be any multiple of 2 up to the degree of the polynomial. The may be 0, 2, or 4 possible non-real zeros.
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<h3>b)</h3>The graph is the first attachment. It shows 4 real zeros: x = -4, -2, 1, 6.
Since the polynomial is of even degree (4) and has a positive leading coefficient (+1), we expect the general shape to be ∪-shaped. It is.
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<h3>c)</h3>The second attachment shows synthetic division using x = -4. (The binomial divisor is (x+4).) The remainder (lower right value in the tableau) is the value of y when x=-4. The third attachment shows synthetic division using the value x=3. (y is -210 when x=3.)
Maybe this is the table you want:
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<h3>d)</h3>The second attachment shows synthetic division by the factor (x+4).
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<em>Additional comment</em>
The synthetic division attachments show instructions for carrying out the synthetic division and interpreting the results. As we said above, "the entry on the left" is the opposite of the constant in the binomial divisor. It is the actual value of x you want to use to evaluate the function.
The equations shown are merely for the purpose of indicating the operations that are used. An actual synthetic division tableau is simply a 3-row table of numbers, with the bottom row being the quotient coefficients and remainder.
