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The polynomial function p is defined by ...

The polynomial function p is defined by `p(x)=4x^(3)+bx^(2)+41x+12`, where b is a constant. When graphed on a standard coordinate plane, p intersects the x-axis at `(-0.25, 0), (3, 0) and (k, 0)`. What is the value of b?

A

`-27`

B

`-sqrt(207)`

C

`4`

D

`27`

Text Solution

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The correct Answer is:
To find the value of \( b \) in the polynomial function \( p(x) = 4x^3 + bx^2 + 41x + 12 \), given that it intersects the x-axis at the points \( (-0.25, 0) \), \( (3, 0) \), and \( (k, 0) \), we can follow these steps: ### Step 1: Substitute the x-value of one intersection point into the polynomial We will use the point \( (3, 0) \) for our calculations since it is an integer and easier to work with. We substitute \( x = 3 \) into the polynomial: \[ p(3) = 4(3)^3 + b(3)^2 + 41(3) + 12 \] ### Step 2: Calculate \( p(3) \) Calculating each term: - \( 4(3)^3 = 4 \times 27 = 108 \) - \( b(3)^2 = 9b \) - \( 41(3) = 123 \) - The constant term is \( 12 \) Putting it all together: \[ p(3) = 108 + 9b + 123 + 12 \] ### Step 3: Set the equation to zero Since \( p(3) = 0 \) (because it intersects the x-axis at this point), we set the equation to zero: \[ 108 + 9b + 123 + 12 = 0 \] ### Step 4: Simplify the equation Combine the constant terms: \[ 108 + 123 + 12 = 243 \] So, we have: \[ 243 + 9b = 0 \] ### Step 5: Solve for \( b \) Now, isolate \( b \): \[ 9b = -243 \] \[ b = \frac{-243}{9} = -27 \] ### Conclusion The value of \( b \) is \( -27 \). ---

To find the value of \( b \) in the polynomial function \( p(x) = 4x^3 + bx^2 + 41x + 12 \), given that it intersects the x-axis at the points \( (-0.25, 0) \), \( (3, 0) \), and \( (k, 0) \), we can follow these steps: ### Step 1: Substitute the x-value of one intersection point into the polynomial We will use the point \( (3, 0) \) for our calculations since it is an integer and easier to work with. We substitute \( x = 3 \) into the polynomial: \[ p(3) = 4(3)^3 + b(3)^2 + 41(3) + 12 \] ...
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  • The function f is defined by f(x)=x^4-4x^4 -x^2+cx -12 , where c is a constant.In the xy-plane, the graph of f intersects the x-axis in the four points (-2,0), (1,0), (p,0), and (q,0). What is the value of c ?

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