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3 years ago

6

A person has three times as many nickels as quarters. if the total face value of these coins is $4.40, how many of each type of

coin does this person have?

1 answer:

saul85 [17]3 years ago

6 0

3 nickels and 1 quarter add to $0.40.
The person has 11 times that amount, so has 11 quarters and 33 nickels.

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Which decimal is equivalent to 25/6?

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4.166666667

Step-by-step explanation:

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3 years ago

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125.504587156 rounded to the nearest whole number

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Use implicit differentiation to find the points where the parabola defined by x2−2xy+y2+4x−8y+20=0 has horizontal and vertical t

Komok [63]

Answer:

The parabola has a horizontal tangent line at the point (2,4)

The parabola has a vertical tangent line at the point (1,5)

Step-by-step explanation:

Ir order to perform the implicit differentiation, you have to differentiate with respect to x. Then, you have to use the conditions for horizontal and vertical tangent lines.

-To obtain horizontal tangent lines, the condition is:

$\frac{dy}{dx}=0$ (The slope is zero)

--To obtain vertical tangent lines, the condition is:

$\frac{dy}{dx}=\frac{1}{0}$ (The slope is undefined, therefore the denominator is set to zero)

Derivating respect to x:

$\frac{d(x^{2}-2xy+y^{2}+4x-8y+20)}{dx} = \frac{d(x^{2})}{dx}-2\frac{d(xy)}{dx}+\frac{d(y^{2})}{dx}+4\frac{dx}{dx}-8\frac{dy}{dx}+\frac{d(20)}{dx}$ = $2x -2(y+x\frac{dy}{dx})+2y\frac{dy}{dx}+4-8\frac{dy}{dx}= 0$

Solving for dy/dx:

$\frac{dy}{dx}(-2x+2y-8)=-2x+2y-4\\\frac{dy}{dx}=\frac{2y-2x-4}{2y-2x-8}$

Applying the first conditon (slope is zero)

$\frac{2y-2x-4}{2y-2x-8}=0\\2y-2x-4=0$

Solving for y (Adding 2x+4, dividing by 2)

y=x+2 (I)

Replacing (I) in the given equation:

$x^{2}-2x(x+2)+(x+2)^{2}+4x-8(x+2)+20=0\\x^{2}-2x^{2}-4x+x^{2} +4x+4+4x-8x-16+20=0\\-4x+8=0\\x=2$

Replacing it in (I)

y=(2)+2

y=4

Therefore, the parabola has a horizontal tangent line at the point (2,4)

Applying the second condition (slope is undefined where denominator is zero)

2y-2x-8=0

Adding 2x+8 both sides and dividing by 2:

y=x+4(II)

Replacing (II) in the given equation:

$x^{2}-2x(x+4)+(x+4)^{2}+4x-8(x+4)+20=0\\x^{2}-2x^{2}-8x+x^{2}+8x+16+4x-8x-32+20=0\\-4x+4=0\\x=1$

Replacing it in (II)

y=1+4

y=5

The parabola has vertical tangent lines at the point (1,5)

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3 years ago

Tiffany babysits to earn extra money. She charges a fee of $15 per hour for one child, and then an added $30 overall for each ad

Hoochie [10]

Answer: Minimum for $150: 2 Hours

Step-by-step explanation: First, Tiffany charges $30 per additional child. If she babysits for 4 children, you do 30 x 4, which is equal to 120. That would be the cost for the children. Now, if she charges $15 PER HOUR, then you just add up $15 + $15, which is $30, and you add that $30 to the $120. Which is $150. There you have it. If this is wrong, correct me please!

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2 years ago

Which variable is the dependent variable--the variable that depended on the treatment and was measured by the researchers? is th

Charra [1.4K]

Answers:

1) Yes. The "variable that depended on treatment and was measured by the researchers" is, in fact, the "dependent variable".

2) The "dependent variable" is on the "y-axis" ; whereas the independent variable is on the "x-axis" .
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3 years ago