9x-5, I guess, not sure, but I'm combining like terms. Hope it's right.
Answer:

Step-by-step explanation:
The marginal cost function, C'(x), is the derivate of the cost function, C(x).
Therefore, we can obtain the cost function by finding the integral of the marginal cost function:

Where 'a' is a constant and represents fixed costs. If fixed costs are $3,000, the cost function is:

Answer:

Step-by-step explanation:
Given the system of equations:


In order to find the y coordinate of the solution we must first find the solution to this system of equations. We first start by solving one of the given equations and then substitute the answer of that into the second equation and further solve to get the final answers.




















Hope this helps.
Answer:
∠ DAB = 48°
Step-by-step explanation:
The sum of the 3 angles in Δ ACD = 180° , then
∠ CAD + 60° + 90° = 180° , that is
∠ CAD + 150° = 180° ( subtract 150° from both sides )
∠ CAD = 30°
Then
∠ DAB + ∠ CAD = ∠ CAB
∠ DAB + 30° = 78° ( subtract 30° from both sides )
∠ DAB = 48°