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3 years ago

Which answer is it ?

Mathematics

2 answers:

Naily [24]3 years ago

4 0

Answer:

-3/4

Step-by-step explanation:

The slope = rise / run, it has gone down 3 so has rise -3 and gone along 4 so run of 4

dsp733 years ago

3 0

The answer to this is -3/4

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The coordinates of the endpoints of ST are (-2,3) and (3, y) respectively supposethe distance between s and t us 13 units.What v

igor_vitrenko [27]

Answer:

The values of y would be -9 and 15

Step-by-step explanation:

we know that

the formula to calculate the distance between two points is equal to

$d=\sqrt{(y2-y1)^{2}+(x2-x1)^{2}}$

we have

$d=13\ units$

S(-2,3) and T(3,y)

substitute the given values in the formula and solve for y

$13=\sqrt{(y-3)^{2}+(3+2)^{2}}$

$13=\sqrt{(y-3)^{2}+25}$

squared both sides

$169=(y-3)^{2}+25$

$(y-3)^{2}=169-25$

$(y-3)^{2}=144$

take square root both sides

$y-3=(+/-)12$

$y=3(+/-)12$

$y=3(+)12=15$

$y=3(-)12=-9$

therefore

The values of y would be -9 and 15

5 0

4 years ago

Solve for y 2x+y-3z=5

Elza [17]

Answer:

Step-by-step explanation:

Isolate the term of x and y from one side of the equation.

<u>To solve:</u>

The value of y.

$\Longrightarrow: \sf{\sqrt{2x+y-3z}=5}$

<u>First, you have to subtract by 2x-3z from both sides.</u>

$\Longrightarrow: \sf{2x+y-3z-\left(2x-3z\right)=25-\left(2x-3z\right)}}$

<u>Solve.</u>

$\Longrightarrow: \boxed{\sf{y=25-2x+3z}}}$

<u>Therefore, the correct answer is "A. y=-2x+3z+25".</u>

I hope this helps, let me know if you have any questions.

4 0

2 years ago

Read 2 more answers

2. The number of atoms of a particular chemical element is modelled by

____ [38]

9514 1404 393

Answer:

a) 600

b) see below

c) 1.26 hours

Step-by-step explanation:

a) The value of y when x=0 is the coefficient of the exponential term:

y = 600·3^(-0) = 600·1 = 600

There were 600 atoms to start.

b) see attached for a graph

c) The graph shows 150 atoms at t = 1.26, about 1.26 hours after the start of time counting.

If you want to find that value algebraically, substitute for y and solve for x. Logarithms are involved.

150 = 600·3^(-x)

150/600 = 3^(-x)

log(1/4) = -x·log(3)

x = -log(1/4)/log(3) = log(4)/log(3) ≈ 1.2618595

After about 1.26 hours, there were 150 atoms.

6 0

3 years ago

I need help, please help me soon<br><br> 12/18/2020<br> 2:06 pm [Eastern time]

Anestetic [448]

Answer: its not 22 its 25

Step-by-step explanation: if it not correcnt than sorry wrong answer

4 0

3 years ago

Read 2 more answers

A radio telescope has a parabolic surface, as shown below.

krek1111 [17]

OK, so the graph is a parabola, with points x=0,y=0; x=6,y=-9; and x=12,y=0

Because the roots of the equation are 0 and 12, we know the formula is therefore of the form

y = ax(x - 12), for some a

So put in x = 6

-9 = 6a(-6)

9 = 36a

a = 1/4

So the parabola has a curve y = x(x-12) / 4, which can also be written y = 0.25x² - 3x

The gradient of this is dy/dx = 0.5x - 3

The key property of a parabolic dish is that it focuses radio waves travelling parallel to the y axis to a single point. So we should arrive at the same focal point no matter what point we chose to look at. So we can pick any point we like - e.g. the point x = 4, y = -8

Gradient of the parabolic mirror at x = 4 is -1

So the gradient of the normal to the mirror at x = 4 is therefore 1.

Radio waves initially travelling vertically downwards are reflected about the normal - which has a gradient of 1, so they're reflected so that they are travelling horizontally. So they arrive parallel to the y axis, and leave parallel to the x axis.

So the focal point is at y = -8, i.e. 1 metre above the back of the dish.

5 0

2 years ago