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Setler [38]
2 years ago
8

What is the elimination of 20x+5y=120 and 10x+7.5=80

Mathematics
1 answer:
Grace [21]2 years ago
5 0
20x+5y=120
10x+7.5y=80    multiply this one by 2
___________

20x+5y=120
20x+15y=160   subtract 

___________

        -10y=-40    divide both sides by -10 
____________

             y=4         

20x+5(4)=120   plug 4 in for y in the first equation 
20x+20=120     multiply 
20x=100           subtract 
x=5                   divide to find x




 
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What’s 4x4x2-4 in a fraction over 2
JulijaS [17]

Answer:

it should be 12/2 or 6 i believe

Step-by-step explanation:

4x4 = 8

8x2 = 16

16-4 = 12

8 0
2 years ago
A recipe states that 5 servings of peanuts have 1,250calories. How many calories is 2 servings of peanuts? *
MrMuchimi

Answer:

500 calories

Step-by-step explanation:

divide the 1250 calories by the initial five servings and you get 250 then multiply that by the 2 servings they are asking for and you get 500 calories

4 0
2 years ago
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A stone is dropped into a barrel of water and sinks to the bottom. The ball is completely covered by water. By how much does the
Rom4ik [11]

Answer:

Answer: 5/12 or approx. 0.42

Step-by-step explanation:

The ball will displace as much water as its volume.

Meaning, the volume of the ball and the volume of the increase in water in the barrel will be equal.

Volume of a sphere:

V_s=\frac{4}{3} \pi r^3

The radius is half the diameter. The diameter of the sphere is 10, thus:

r = d/2 = 10/2 = 5

5^3 = 5*5*5 = 25*5 = 125

V_s=\frac{4}{3} \pi * 5^3=\frac{4}{3} \pi * 125

The volume of a cylinder, which will be the shape of the increase in water, is the following:

V_c=\pi r^2 h

We know the radius r, as we know the diameter.

r=d/2=40/2=20

V_c=\pi r^2 h=\pi h * 20^2 = \pi h * 400

We are looking for the height of the cylinder, h, as that will be the height of the water rise.

Since we know these 2 volumes are the same, we'll set them equal to each other and solve the equation:

V_s = V_c

\frac{4}{3} * 125 * \pi = 400 * h * \pi

We can get rid of pi by dividing both sides by pi:

\frac{4}{3} * 125 = 400 * h

And now divide both sides by 400:

\frac{4}{3} * \frac{125}{400}= h

Just reversing it and putting h to the left:

h = \frac{4}{3} * \frac{125}{400} = \frac{4 * 125}{3 * 400}

I see that I can divide both the numerator and the denominator by 4:

h =\frac{125}{3 * 100}= \frac{125}{300}

I'll now divide both the numerator and the denominator by 25 to simplify the expression:

h=\frac{125}{300} =\frac{125 / 25}{300 / 25} = \frac{5}{12}

Answer: The water rises by 5/12 (five twelfths).

If I want an approximate decimal answer, I can simply run this expression in a calculator:

\frac{5}{12} ≈ 0.416666667 ≈ 0.42

7 0
2 years ago
The function D(t) defines a traveler's distance from home, in miles, as a function of time, in hours. D(t) = StartLayout enlarge
nalin [4]

- At 2 hours, the traveler is 725 miles from home.

- At 3 hours, the distance is constant, at 880 miles. --> TRUE.

- The total distance from home after 6 hours is 1,062.5 miles --> TRUE.

Step-by-step explanation:

The function D(t) is defined as follows:

D(t) = 300t+125 for t< 2.5

D(t) = 880 for 2.5 \leq 3.5

D(t) = 75t+612.5 for t\leq 6

Where

t is the time in hours

D(t) is the distance covered, in miles, after t hours

Now let's analyze the different statements:

- The starting distance, at 0 hours, is 300 miles. --> FALSE. In fact, if we substitute t = 0 into the 1st equation, we get

D(0) = (300)(0)+125 = 125

So, the distance at t = 0 is 125 miles.

- At 2 hours, the traveler is 725 miles from home. --> TRUE. In fact, if we substitute t = 2 into the 1st equation,

D(2) = (300)(2)+125 = 725

- At 2.5 hours, the traveler is 875 miles from home. --> FALSE. In fact, for t=2.5 we have to use the 2nd equation, which states that the distance is:

D(t) = 880

So, not 875 miles.

- At 3 hours, the distance is constant, at 880 miles. --> TRUE. This is clearly visible from the 2nd equation: for t between 2.5 and 3.5 (so, in this case), the distance is

D(t) = 880

- The total distance from home after 6 hours is 1,062.5 miles --> TRUE. In fact, if we replace t = 6 into the last equation,

D(6)) = 75(6)+612.5=1062.5

Learn more about functions:

brainly.com/question/3511750

brainly.com/question/8243712

brainly.com/question/8307968

Learn more about  distance:

brainly.com/question/3969582

#LearnwithBrainly

4 0
1 year ago
Read 2 more answers
Quadrilateral A’B’C’D’ is a dilation of quadrilateral ABCD about point P. Quadrilateral ABCD is shown. Side AB is labeled 5. Sid
Stolb23 [73]

Answer:  The correct option is (A) reduction.

Step-by-step explanation:  Given that the quadrilateral A'B'C'D' is a dilation of the quadrilateral ABCD.

As shown in the given figure, the lengths of the sides of quadrilateral ABCD are as follows:

AB = 5 units, BC = 4 units, CD = 10 units and DA = 6 units.

And, the lengths of the sides of quadrilateral A'B'C'D' are as follows:

A'B'=1\dfrac{1}{4}=\dfrac{5}{4}~\textup{units},~~B'C'=1~\textup{units},~~C'D'=2\dfrac{1}{2}=\dfrac{5}{2}~\textup{units},\\\\D'A'=1\dfrac{1}{2}=\dfrac{3}{2}~\textup{units}.

We know that the dilation will be an enlargement if the scale factor is greater than 1 and it will be a reduction if the scale factor is less than 1.

Now, the scale factor is given by

S=\dfrac{\textup{length of a side of the dilated figure}}{\textup{length of the corresponding side of the original figure}}\\\\\\\Rightarrow S=\dfrac{A'B'}{AB}=\dfrac{\frac{5}{4}}{5}=\dfrac{5}{4\times5}=\dfrac{1}{4}

Since the scale factor is less than 1, so the dilation will be a reduction.

5 0
1 year ago
Read 2 more answers
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