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4 years ago

Solve: 16x2 − 81 = 0

Mathematics

2 answers:

MrRa [10]4 years ago

8 0

Answer:

x =±9/4

Step-by-step explanation:

16x^2 − 81 = 0

Add 81 to each side

16x^2 − 81 +81 = 81

16 x^2 =18

Divide by 16

x^2 =81/16

Take the square root of each side

sqrt(x^2) = sqrt(81/16)

x =±9/4

Musya8 [376]4 years ago

7 0

16 x 2 - 81

32-81

= -49

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You start at home by walking 10 meters west, turning south, and then walking 5 more meters. Find the distance from home. Round t

wel

Answer:

5sqrt(5) meters

Step-by-step explanation:

Picture a right triangle with one horizontal leg and one vertical leg, as well as the hypotenuse. Walking 10 meters west is represented horizontally. Likewise, walking 5 meters south is represented vertically. This right triangle thus has two legs of lengths 10 m and 5 m respectively; according to the Pythagorean Theorem, the length of the diagonal (which represents the distance from home) is d = sqrt(10^2 + 5^2) = sqrt(125) = 5sqrt(5). Round this off to the nearest tenth m (meter or mile) after evaluating the square root on a calculator.

8 0

3 years ago

Pam has 90 m of fencing to enclose an area in a petting zoo with two dividers to separate three types of young animals. The thre

andrew-mc [135]

Answer:

The area function is

$A=\frac{135}{2}x-\frac{9}{2}x^2$ .

The domain and range of A is $(0,15m)$ and $(0, 253.125 m^2]$ .

Step-by-step explanation:

The given length of fencing is $90 m$ .

Let the length and width of each pen be $x$ and $y$ respectively as shown in the figure.

As there are 3 pens, so, the total area,

$A= 3 xy \;\cdots (i)$

From the figure the total length of fencing is $6x+4y$ .

Here, for a significant area for the animals, $x>0$ as well as $y>0$ as $x$ and $y$ are the sides of ben.

From the given value:

$6x+4y=90\;\cdots (ii)$

$\Rightarrow y=\frac {45}{2}-\frac{3x}{2}$

Now, from equation (i)

$A=3x\left(\frac {45}{2}-\frac{3x}{2}\right)$

$\Rightarrow A=\frac{135}{2}x-\frac{9}{2}x^2\;\cdots (iii)$

This is the required area function in the terms of variable $x$ .

For the domain of area function, from equation (ii)

$x=15-\frac{2y}{3}$

$\Rightarrow x$ [as y>0]

So, the domain of area function is $(0,15m)$ .

For the range of area function:

As $x \rightarrow 0$ or $y\rightarrow 0$ , then $A\rightarrow 0$ [from equation (i)]

$\Rightarrow A>0$

Now, differentiate the area function with respect to $x$ .

$\frac {dA}{dx}=\frac{135}{2}-9x$

Equate $\frac {dA}{dx}$ to zero to get the extremum point.

$\frac {dA}{dx}=0$

$\Rightarrow \frac{135}{2}-9x=0$

$\Rightarrow x=\frac{15}{2}$

Check this point by double differentiation

$\frac {d^2A}{dx^2}=-9$

As, $\frac {d^2A}{dx^2}$ , so, point $x=\frac{15}{2}$ is corresponding to maxima.

Put this value back to equation (iii) to get the maximum value of area function. We have

$A=\frac{135}{2}\times \frac {15}{2}-\frac{9}{2}\times \left(\frac {15}{2}\right)^2$

$\Rightarrow A=253.125 m^2$

Hence, the range of area function is $(0, 253.125 m^2]$ .

4 0

4 years ago

Please solve if you know no trolls please im desparate

IgorC [24]

The question isn’t equal to 90° it’s equal to 180° because the line is straight it’s not a right angle. so when u equal the whole equation to 180°, you get x=18.75. then plug in the number to find the degree of each.
so angle of department would be 139.25° and angle of gas station would be 40.75°

3 0

3 years ago

At a school number of boys : number of girls = 11 : 9

aliya0001 [1]

Ok, so 11:9
11-9 = 2
which means that 124= 2:1
124/2 = 62
so 62:0
now 11 x 62= 682
9 x 62= 558

so the ratio is 682:558
now 682 + 558 = 1,240
There are 1,240 total students in the school. 682 boys and 558 girls

8 0

3 years ago

What is the 6th term of the geometric sequence where a1 = 1,024 and a4 = −16? 1 −0.25 −1 0.25

VLD [36.1K]

The n-th term is given by

$a_n=a_1\cdot r^{(n-1)}\qquad\text{where r is the common ratio}$

Then we can find the common ratio from the given terms.

$\dfrac{a_4}{a_1}=\dfrac{a_1\cdot r^{(4-1)}}{a_1}=r^3=\dfrac{-16}{1024}=\left(\dfrac{-1}{4}\right)^3\\\\r=\dfrac{-1}{4}\\\\a_6=1024\left(\dfrac{-1}{4}\right)^5=-1$

The appropriate choice is -1.

8 0

4 years ago

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