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3 years ago

A video store is selling previously owned DVD'S for 40% off the regular price of $15. What is the sale price of the DVD's?

Mathematics

1 answer:

belka [17]3 years ago

5 0

Answer:$9

Step-by-step explanation:

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Please help me answer this question genius

kolbaska11 [484]

Answer:

x ∈ {-0.465, 1.014}

Step-by-step explanation:

The equation can be cast in the form f(x) = 0, and solved easily using a graphing calculator. That shows x ≈ -0.465 and x ≈ 1.014. The same calculator can iterate the roots to full calculator precision.

The equation can be made a quadratic by the substitution ...

z = e^(2x)

Then we have ...

$2\cosh(2x)-\sinh(2x)=4\\\\2\cdot\dfrac{e^{2x}+e^{-2x}}{2}-\dfrac{e^{2x}-e^{-2x}}{2}-4=0\qquad\text{use exponential identities}\\\\2z+2z^{-1}-z+z^{-1}-8=0\qquad\text{multiply by 2, substitute z}\\\\z^2 -8z+3=0\qquad\text{multiply by z}\\\\z=\dfrac{8\pm\sqrt{(-8)^2-4(1)(3)}}{2(1)}=4\pm\sqrt{13}\\\\x=\dfrac{\ln(z)}{2}=\dfrac{\ln(4\pm\sqrt{13})}{2}\approx\{-0465133,1.014439\}$

7 0

2 years ago

The cost function for q units of a certain item is C(q)equals109 q plus 90. The revenue function for the same item is R(q)equa

Tcecarenko [31]

Answer:

a) $109

b) $P(q) = \frac{45q}{ln(q)} +90$

c) $$11.20$

Step-by-step explanation:

a) The marginal cost, or the cost per additional unit, is given by the derivate of the cost function:

$C(q) = 109q+90\\C(q) = \$109$

b) Profit is given by Revenue minus Cost:

$P(q) = R(q) - C(q)\\P(q) = \frac{45q}{ln(q)} +90$

c) The marginal profit for 8 units, is given by the difference in profit for 9 units and 8 units:

$M = P(9)-P(8)\\M= \frac{45*9}{ln(q)} +90 - (\frac{45*8}{ln(8)}+90 )\\M=\$11.20$

6 0

2 years ago

Elaine travelled 354.9 miles on her last tank of gas. When she stopped to get gas, her car required 9.1 gallons of gas. How many

nikdorinn [45]

354.9/9.1=39

So. elaine averaged 39 miles per gallon

5 0

3 years ago

Apply the distribution property to produce an equivalent expression 2(7g + 7)

ira [324]

21+g or it could be(still the same thing) 21 + 1g

3 0

3 years ago

Winston earns $140.00 by selling 56 hot dogs at a concession stand at school. Using the same rate for the cost of one hot dog, h

kvv77 [185]

Step by step explanation

Cost of one hotdog =140/56=2.5

To find the number of hot dogs =total cost so the cost of one hotdog is =175/2.5=70

So the numbers of hot dogs he had to sell more of =70-56=14

3 0

2 years ago