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3 years ago

Suppose the area of a circle is 4π. What is its diameter?

2 answers:

6 0

Area=pi times radius^2 so

if area=4pi=pi times r^2
4 times pi=r^2 times pi
divide both sdies by pi
4=r^2
square root
2=radius since legnth cannot be negative

radius=1/2 diamters
2 radius=diameter
2(2)=diameter=4
diameter=4

Ganezh [65]3 years ago

6 0

$A=4\pi=\pi r^2\\
4\pi=\pi r^2\\
r^2=4\\
r=2\\\\
d=2r\\
d=2\cdot2\\
d=4$

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Find all roots: x^3 + 7x^2 + 12x = 0 Show all work and check your answer.

Aliun [14]

The three roots of x^3 + 7x^2 + 12x = 0 is 0,-3 and -4

Solution:

We have been given a cubic polynomial.

$x^{3}+7 x^{2}+12 x=0$

We need to find the three roots of the given polynomial.

Since it is a cubic polynomial, we can start by taking ‘x’ common from the equation.

This gives us:

$x^{3}+7 x^{2}+12 x=0$

$x\left(x^{2}+7 x+12\right)=0$ ----- eqn 1

So, from the above eq1 we can find the first root of the polynomial, which will be:

x = 0

Now, we need to find the remaining two roots which are taken from the remaining part of the equation which is:

$x^{2}+7 x+12=0$

we have to use the quadratic equation to solve this polynomial. The quadratic formula is:

$x=\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}$

Now, a = 1, b = 7 and c = 12

By substituting the values of a,b and c in the quadratic equation we get;

$\begin{array}{l}{x=\frac{-7 \pm \sqrt{7^{2}-4 \times 1 \times 12}}{2 \times 1}} \\\\{x=\frac{-7 \pm \sqrt{1}}{2}}\end{array}$

Therefore, the two roots are:

$\begin{array}{l}{x=\frac{-7+\sqrt{1}}{2}=\frac{-7+1}{2}=\frac{-6}{2}} \\\\ {x=-3}\end{array}$

And,

$\begin{array}{c}{x=\frac{-7-\sqrt{1}}{2}} \\\\ {x=-4}\end{array}$

Hence, the three roots of the given cubic polynomial is 0, -3 and -4

4 0

3 years ago

If 4 (x-2/3) = -18, what is the value of 2x

BaLLatris [955]

Answer:

-11.5

Step-by-step explanation:

4(x-2/3)=-18

4x-8/3=-18

4x-8=-18×3

4x-8=-54

4x=-54+8

4x=-46

x=-46/4

x=-11.5

4 0

3 years ago

Leo and her on spent 3/4 hour shopping 5/6 hour preparing the pizzas and 11/12 hour cleaning up after the party how many minutes

Aneli [31]

Answer:

150 minutes

Step-by-step explanation:

First we have to express all these fractions of an hour in minutes, then add them and get the total of minutes.

To pass these numbers in hours to minutes, we only have to multiply by 60 because one hour has 60 minutes.

3/4 h =

3/4 * 60 = 45m

5/6 h =

5/6 * 60 = 50m

11/12 h =

11/12 * 60 = 55m

to calculate the total number of minutes we have to add the 3 values that we have

45m + 50m + 55m = 150m

8 0

3 years ago

Chance knows the length of a football field (including end zones) is 120 yards. The width of the field is 53.33 yards. What is t

givi [52]

Answer = about 6,400 yards squared

Step-by-step explanation:

4 0

3 years ago

Convert 65,000,000 to scientific notation.

Sophie [7]

Answer:

6.5 x 10^7. PLEASE MARK BRAINLIEST IF THIS HELPS.

Step-by-step explanation:

Well, its kind of hard to explain but i'll do my best.

65,000,000 has six zeros, and in order to get the answer, you have to put the answer into a decimal. So all you have to do is put the decimal right here. 65000000.< Hope that makes sense. Then all you have to do is move that decimal to the left however many times is needed to make the answer a decimal (in this case it is 7 times). Which makes the answer 6.5 but your not done yet, then, since you had to move to the left seven times in order to get your decimal, that means the second part of your answer is 10^7, (10 to the seventh power) since you moved seven times. Example: if you had had to move to the left 9 times to get your decimal, then it would have been 10^9, if that makes any sense. So that means your final product would be 6.5 x 10^7

8 0

3 years ago

Read 2 more answers