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Kay [80]
3 years ago
15

Using substitution to solve the system below, what expression should be substituted into the first equation? 2x-4y=-4 and x+2y=8

Mathematics
2 answers:
inna [77]3 years ago
5 0

Answer:

Given the system of equation:

2x-4y=-4                    ......[1]

x+2y=8                      ......[2]

we can rewrite equation [2] as;

x = 8-2y                ......[3]

Substitute equation [3] into [1] to eliminate x, and solve for y;

2(8-2y)-4y = -4

Using distributive property: a\cdot (b+c) = a\cdot b+ a\cdot c

16-4y -4y = -4

Combine like terms;

16 - 8y = -4

Add 4 to both sides we have;

20 - 8y = 0

Add 8y to both sides we have;

20 = 8y

Divide 8 to both sides we have;

y = 2.5

Substitute the y-value in [3] we have;

x = 8-2(2.5)

x = 8 - 5 = 3

Therefore, the  expression should be substituted into the first equation is, x = 8-2y  and also the value of x = 3 and y = 2.5

MA_775_DIABLO [31]3 years ago
5 0

Answer:


Step-by-step explanation:

Choices?

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Serena has attached a 10 inch ribbon to the corners of a frame to hang it on the wall. The frame 9 inches wide. How far above th
kherson [118]

Answer: The hook would be 2.2 inches (approximately) above the top of the frame

Step-by-step explanation: Please refer to the picture attached for further details.

The top of the picture frame has been given as 9 inches and a 10 inch ribbon has been attached in order to hang it on a wall. The ribbon at the point of being hung up would be divided into 5 inches on either side (as shown in the picture). The line from the tip/hook down to the frame would divide the length of the frame into two equal lengths, that is 4.5 inches on either side of the hook. This would effectively give us two similar right angled triangles with sides 5 inches, 4.5 inches and a third side yet unknown. That third side is the distance from the hook to the top of the frame. The distance is calculated by using the Pythagoras theorem which states as follows;

AC^2 = AB^2 + BC^2

Where AC is the hypotenuse (longest side) and AB and BC are the other two sides

5^2 = 4.5^2 + BC^2

25 = 20.25 + BC^2

Subtract 20.25 from both sides of the equation

4.75 = BC^2

Add the square root sign to both sides of the equation

2.1794 = BC

Rounded up to the nearest tenth, the distance from the hook to the top of the frame will be 2.2 inches

4 0
3 years ago
Number 18 plz. I really need help
elixir [45]
The answer is 87. it was quite simple


7 0
3 years ago
ASAP PLEASE HELP!!!!
zzz [600]

Answer:

It will take Josie 80 minutes to run 10 miles.

Step-by-step explanation:

We can set up a proportion between the number of minutes she runs to the number of miles she runs. From what we know in the equation, we know that it takes her 24 minutes to run 3 miles, and it takes x minutes to run 10 miles. We can represent this in a proportion!

We know that the ratio of 24:3 will be the same for any number of miles, so we can say

\frac{24}{3} =\frac{x}{10\\}

We can solve this by first simplifying the left hand side then isolation x by multiple both sides of the equation by 10.

24/3 = 8

8 = \frac{x}{10}

80 = x

It will take Josie 80 minutes to run 10 miles.

8 0
3 years ago
Read 2 more answers
What are examples of nonstatistical question
posledela

Answer:

The type of questions that has only one answer.

Step-by-step explanation:

example:

What time did Katy wake up? Did you eat lunch?

7 0
3 years ago
Find an equation of the circle and sketch it if it has: Center on y=4, tangent x-axis at (–2, 0)
Digiron [165]

Answer:

(x+2)^2+(y-4)^2=16

OK, lets start by drawing a basic graph (the first one) so we can visualize.

We already know that the y coordinate of the circle's center is 4.

We know that the circle is tangent to the X axis at (-2,0)

That means the x coordinate of the center has to be -2, as the tangent is a point on the edge of the circle that touches a line at exactly one point.

The radius is the distance from the center of the circle to its edge. We know the center's location now, it is (-2, 4) and a point on the edge of the circle (the tangent point) which is (-2,0). so the distance between the points is 4 which is the radius (you can use the distance formula, but it's quite oblivious.)

We can imagine the circle should look like this (the second one):

Now we can piece together an equation

The equation of a circle is (x-h)^2+(y-k)^2=r^2 where (h,k) is the center and r is the radius. When we put the numbers in: we get (x-(-2))^2+(y-(4))^2=4^2 which can be simplified into (x+2)^2+(y-4)^2=16 which is the answer.

Step-by-step explanation:

4 0
3 years ago
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