Given that f(x) = x^2 + 4x, evaluate f(-2)

2 answers:

8 0

Hi there!

To find f(-2), we need to plug in the value x = -2 into the equation.

$f( - 2) = ( - 2) {}^{2} + 4 \times - 2 = 4 - 8 = - 4$
Remember that multiplying a negative by a positive ends up with a positive.

~ Hope this helps you!

vovangra [49]3 years ago

3 0

Hi there!

• f(x) = x² + 4x

• Then,
For finding th' value of f(-2). Substitute " -2 " in place of " x "

f(-2) = (-2)² + 4 × - 2

Exponents first. Accr'ding to P.E.M.D.A.S.

f(-2) = 4 + 4 × - 2

f(-2) = 4 + (-8)

f(-2) = 4 - 8

f(-2) = - 4

Hence, f(-2) = - 4

~ Hope it helps!

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MakcuM [25]

Answer:

Step-by-step explanation:

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5 0

4 years ago

Read 2 more answers

Can someone help please

myrzilka [38]

<h3>Answer: 15x^(7/3) - 8x^(7/4) + x + 9000</h3>

=========================================================

Explanation:

If you know the cost function C(x), to find the marginal cost, we apply the derivative.

Marginal cost = derivative of cost function

Marginal cost = C ' (x)

Since we're given the marginal cost, we'll apply the antiderivative (aka integral) to figure out what C(x) is. This reverses the process described above.

$\text{Cost} = \text{antiderivative of marginal cost}\\\\\displaystyle C(x) = \int \left(35x^{4/3} - 14x^{3/4} + 1\right)dx\\\\$

$C(x) = \frac{1}{1+4/3}*35x^{4/3+1} - \frac{1}{1+3/4}*14x^{3/4+1} + x + D\\\\C(x) = \frac{1}{7/3}*35x^{7/3} - \frac{1}{7/4}*14x^{7/4} + x + D\\\\C(x) = \frac{3}{7}*35x^{7/3} - \frac{4}{7}*14x^{7/4} + x + D\\\\C(x) = 15x^{7/3} - 8x^{7/4} + x + D\\\\$

D represents a fixed constant. I would have used C as the constant of integration, but it's already taken by the cost function C(x).

To determine the value of D, we plug in x = 0 and C(x) = 9000. This is because we're told the fixed costs are $9000. This means that when x = 0 units are made, you still have $9000 in costs to pay. This is the initial value. You'll find that all of this leads to D = 9000 because everything else zeros out.

Therefore, we go from this

$C(x) = 15x^{7/3} - 8x^{7/4} + x + D\\\\$