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3 years ago

What is the value of x when x+7=21

Mathematics

2 answers:

OLga [1]3 years ago

8 0

Answer: x = 14

Step by Step:

Subtract 21 - 7 to get your answer or you can do this.

7*2 = 14

7*3 = 21

Hope this helps! #BaconSquad

Semmy [17]3 years ago

4 0

Answer:

Step-by-step explanation:

14 + 7 = 21

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You must calculate the number of sheets of plywood needed for subflooring. Each sheet of plywood measures 4'by 8. The measuremen

snow_lady [41]

Answer:

25 sheets of plywood will be needed

Step-by-step explanation:

Each sheet of plywood measures $4ft*8ft=32ft^{2}$ .

We have to cover the surface of the house, minus the surface of the hole of the stairs.

$Surface _{to cover} = Surface _{house} -Surface _{hole}= (28ft*30ft)-(12ft*4ft)= 840ft^{2}-48ft^{2}=792ft^{2}$

To know how many sheets will be needed, we divide the surface to be covered by the surface of each sheet

$Sheets_{needed} =\frac{Surface _{house}}{Surface _{sheet}} =\frac{792ft^{2}}{32\frac{ft^{2}}{sheet} } = 24,75 sheets$

As we can't buy 0,75 of a sheet, we round it up, i.e. we will need 25 sheets of plywood for subflooring.

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3 years ago

A driver drove for 3 hours at a certain speed. If he drove 12 more miles at the same speed, the distance would be 132 miles. At

Zinaida [17]

Distance traveled in 3 hrs was (speed in mph)(3 hrs)

Then s(3 hrs) + 12 mi = 132 mi.

Therefore, 3s = 120, and s = 120 miles / 3 hrs = 40 mph (answer)

7 0

3 years ago

Please help brainliest to correct answer

jekas [21]

The first one is -4 and the second one is 6.

7 0

3 years ago

Read 2 more answers

Please help me! Find the number x such that f(x) =1

STatiana [176]

Answer:

Step-by-step explanation:

We have the piecewise function:

$f(x) = \left\{ \begin{array}{ll} -\frac{1}{2}x-1 & \quad x \leq -2 \\ x & \quad x > -2 \end{array} \right.$

And we want to find x such that f(x)=1.

So, let's substitute 1 for f(x):

$1 = \left\{ \begin{array}{ll} -\frac{1}{2}x-1 & \quad x \leq -2 \\ x & \quad x > -2 \end{array} \right.$

This has two equations. So, we can separate them into two separate cases. Namely:

$1=-\frac{1}{2}x-1\text{ or } 1=x$

Let's solve for x in each case.

Case I:

We have:

$1=-\frac{1}{2}x-1$

Add 1 to both sides:

$2=-\frac{1}{2}x$

Let's cancel out the fraction by multiplying both sides by -2. So:

$2(-2)=(-2)\frac{-1}{2}x$

The right side cancels:

$-4=x\\$

Flip:

$x=-4$

So, x is -4.

Case II:

We have:

$1=x$

Flip:

$x=1$

This is the solution for our second case.

So, we have:

$x_1=-4\text{ or } x_2=1$

Now, can check to see if we have to to remove solution(s) that don't work.

Note that x=-4 is the solution to our first equation.

The first equation is defined only if x is less than -2.

-4 is less than -2. So, x=-4 is indeed a solution.

x=1 is the solution to our second equation.

The second equation is defined only if x is greater than or equal to -2.

1 is greater than or equal to -2. So, x=1 is also a solution.

Therefore, our two solutions are:

$x_1=-4\text{ or } x_2=1$

Out of our answer choices, we can pick D.

And we're done!

7 0

3 years ago

Finding area of shaded sectors.

tekilochka [14]

Answer:

69.81 sq. m. (rounded to 2 decimal places)

Step-by-step explanation:

The sector of a circle is "part" or "portion" of a circle. The formula for the area of a sector is:

$A=\frac{\theta}{360}*\pi r^2$

Where

$\theta$ is the central angle

r is the radius

Given the figure, the arc is given as 80 degrees, but not the central angle of the shaded sector. But from geometry we know that the central angle and the intercepted arc have the same measure. So we can say:

$\theta = 80$

Also, the radius of the circle shown is 10 meters, so

r = 10

Now, we substitute in formula and find our answer:

$A=\frac{\theta}{360}*\pi r^2\\A=\frac{80}{360}*\pi (10)^2\\A=\frac{2}{9}*100\pi\\A=\frac{200\pi}{9}\\A=69.81$

Thus,

The area of the shaded sector is 69.81 sq. meters.

5 0

3 years ago