Here I copy the steps and indicate where the error is.
Square root of negative 2x plus 1 − 3 = x=> <span>this is the starting equation
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√[ - 2x + 1] - 3 = x
Square root of negative 2x plus 1 − 3 + 3 = x + 3 in this step she added 3 to each side, which is fine
<span> Square root
of negative 2x plus 1 = x + 3 <span>she made the addtions => fine</span></span>
Square root of negative 2x plus 1 − 1 = x + 3 – 1 due to <span>plus 1 in inside the square root, this step will not help</span>
<span> Square root
of negative 2 x = x + 2 <span>wrong! she cannot simplify - 1 that is out of the square root with +1 that is inside the square root
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<span>Then, from here on all is wrong, but she made other additional mistakes.</span>
(Square root of negative 2 x)2 = (x − 4)2 −2x <span> the right side should be (x+2)^2 which is x^2 + 4x +4 not (x-4)^2 - 2x</span>
Later she made a mistake changing the sign of -8x to +8x
Those are the mistakes. Finally, the global error is that she should verify whether the found values satisfied the original equation.
Answer:
c) d is greater than or equal to 530
Step-by-step explanation:
Hope this helps!
Answer:
17) MC(x) = 35 − 12/x²
18) R(x) = -0.05x² + 80x
Step-by-step explanation:
17) The marginal average cost function (MC) is the derivative of the average cost function (AC).
AC(x) = C(x) / x
MC(x) = d/dx AC(x)
First, find the average cost function:
AC(x) = C(x) / x
AC(x) = (5x + 3)(7x + 4) / x
AC(x) = (35x² + 41x + 12) / x
AC(x) = 35x + 41 + 12/x
Now find the marginal average cost function:
MC(x) = d/dx AC(x)
MC(x) = 35 − 12/x²
18) x is the demand, and p(x) is the price at that demand. Assuming the equation is linear, let's use the points to find the slope:
m = (40 − 50) / (800 − 600)
m = -0.05
Use point-slope form to find the equation of the line:
p(x) − 50 = -0.05 (x − 600)
p(x) − 50 = -0.05x + 30
p(x) = -0.05x + 80
The revenue is the product of price and demand:
R(x) = x p(x)
R(x) = x (-0.05x + 80)
R(x) = -0.05x² + 80x
