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Brrunno [24]
3 years ago
5

The area of a circle is 4π square kilometers. What is the radius? Write your answer in simplest form.

Mathematics
1 answer:
Mariana [72]3 years ago
7 0

Answer:

2 km

Step-by-step explanation:

4π = π × r²

r² = 4

r = 2

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Point slope formula.. help
sertanlavr [38]
<h3>Answer:   y = 2x+6</h3>

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

Explanation:

We'll need the slope first

m = slope

m = (y2-y1)/(x2-x1)

m = (0-(-4))/(-3-(-5))

m = (0+4)/(-3+5)

m = 4/2

m = 2

The slope is 2.

Next, pick either of the two given points to play the role of (x_1,y_1)

Let's say we picked on (-5,-4). The order doesn't matter so you could easily pick the other point as well.

We'll plug these items into the point slope equation below to solve for y.

y - y_1 = m(x - x_1)\\\\y - (-4) = 2(x - (-5))\\\\y  + 4 = 2(x +5)\\\\y  + 4 = 2x +10\\\\y  = 2x +10-4\\\\y  = 2x +6\\\\

Or we could have picked on (-3,0). The m value stays the same (at m = 2)

y - y_1 = m(x - x_1)\\\\y - 0 = 2(x - (-3))\\\\y = 2(x +3)\\\\y = 2x+6\\\\

This one takes a few less steps. Either way, we get to the same answer.

You only need to pick one of the points, but doing both of them helps show that the two points are on the same line. It helps confirm the answer.

-----------------------

Another way to check the answer is to plug the (x,y) coordinates into y = 2x+6 for each point.

So let's say we check (x,y) = (-5,-4)

y = 2x+6

-4 = 2(-5)+6 ... replace x with -5, replace y with -4

-4 = -10+6

-4 = -4

This confirms the first point. I'll let you check the second point.

6 0
2 years ago
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Which equation is equivalent to 4x + y=12? A.y=-4x-32 B.y=-4x+12 c.y=4x+12 D.y=4x-3
Rama09 [41]
The answer is <span>y=-4x+12 because they just moved the 4x

</span>
6 0
3 years ago
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Omar's credit card has an APR of 26% calculated on the previous monthly
wariber [46]

Answer:

  B.  $257.33

Step-by-step explanation:

Interest will be charged on the New Balance after the Month 7 payment, $257.33.

4 0
2 years ago
What is the sum of the complex numbers 2 + 3i and 4 + 8i, where i = <br> −1<br> ?
kotykmax [81]
-1, -4 because 2+3(-1)= -1 and 4+8(-1)= -4
8 0
2 years ago
Read 2 more answers
5^(-x)+7=2x+4 This was on plato
Setler79 [48]

Answer:

Below

I hope its not too complicated

x=\frac{\text{W}_0\left(\frac{\ln \left(5\right)}{2e^{\frac{3\ln \left(5\right)}{2}}}\right)}{\ln \left(5\right)}+\frac{3}{2}

Step-by-step explanation:

5^{\left(-x\right)}+7=2x+4\\\\\mathrm{Prepare}\:5^{\left(-x\right)}+7=2x+4\:\mathrm{for\:Lambert\:form}:\quad 1=\left(2x-3\right)e^{\ln \left(5\right)x}\\\\\mathrm{Rewrite\:the\:equation\:with\:}\\\left(x-\frac{3}{2}\right)\ln \left(5\right)=u\mathrm{\:and\:}x=\frac{u}{\ln \left(5\right)}+\frac{3}{2}\\\\1=\left(2\left(\frac{u}{\ln \left(5\right)}+\frac{3}{2}\right)-3\right)e^{\ln \left(5\right)\left(\frac{u}{\ln \left(5\right)}+\frac{3}{2}\right)}

Simplify\\\\\mathrm{Rewrite}\:1=\frac{2e^{u+\frac{3}{2}\ln \left(5\right)}u}{\ln \left(5\right)}\:\\\\\mathrm{in\:Lambert\:form}:\quad \frac{e^{\frac{2u+3\ln \left(5\right)}{2}}u}{e^{\frac{3\ln \left(5\right)}{2}}}=\frac{\ln \left(5\right)}{2e^{\frac{3\ln \left(5\right)}{2}}}

\mathrm{Solve\:}\:\frac{e^{\frac{2u+3\ln \left(5\right)}{2}}u}{e^{\frac{3\ln \left(5\right)}{2}}}=\frac{\ln \left(5\right)}{2e^{\frac{3\ln \left(5\right)}{2}}}:\quad u=\text{W}_0\left(\frac{\ln \left(5\right)}{2e^{\frac{3\ln \left(5\right)}{2}}}\right)\\\\\mathrm{Substitute\:back}\:u=\left(x-\frac{3}{2}\right)\ln \left(5\right),\:\mathrm{solve\:for}\:x

\mathrm{Solve\:}\:\left(x-\frac{3}{2}\right)\ln \left(5\right)=\text{W}_0\left(\frac{\ln \left(5\right)}{2e^{\frac{3\ln \left(5\right)}{2}}}\right):\\\quad x=\frac{\text{W}_0\left(\frac{\ln \left(5\right)}{2e^{\frac{3\ln \left(5\right)}{2}}}\right)}{\ln \left(5\right)}+\frac{3}{2}

3 0
3 years ago
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