Evaluate f of 4 if f of x equals negative 2 x squared plus 5x minus 8.

Evaluate f of 4 if f of x equals negative 2 x squared plus 5x minus 8.

• A. -20
• B. 20
• C. -16
• D. 16

Answer: (A)

To evaluate \( f(4) \) for the function \( f(x) = -2x^2 + 5x - 8 \), you start by substituting \( x \) with 4 in the equation. First, calculate \( 4^2 \): \[ 4^2 = 16. \] Then, substitute 4 into the function: \[ f(4) = -2(16) + 5(4) - 8. \] Now do the multiplications: \[ -2(16) = -32, \] and \[ 5(4) = 20. \] Insert these values back into the equation: \[ f(4) = -32 + 20 - 8. \] Next, perform the addition and subtraction: \[ -32 + 20 = -12, \] Then, \[ -12 - 8 = -20. \] Therefore, the evaluation yields \( f(4) = -20 \). This confirms that the value of \( f(4) \) is indeed \(-20\).

To evaluate ( f(4) ) for the function ( f(x) = -2x^2 + 5x - 8 ), you start by substituting ( x ) with 4 in the equation.

First, calculate ( 4^2 ):

[

4^2 = 16.

]

Then, substitute 4 into the function:

[

f(4) = -2(16) + 5(4) - 8.

]

Now do the multiplications:

[

-2(16) = -32,

]

and

[

5(4) = 20.

]

Insert these values back into the equation:

[

f(4) = -32 + 20 - 8.

]

Next, perform the addition and subtraction:

[

-32 + 20 = -12,

]

Then,

[

-12 - 8 = -20.

]

Therefore, the evaluation yields ( f(4) = -20 ).

This confirms that the value of ( f(4) ) is indeed (-20).