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Mrrafil [7]
3 years ago
14

How to find X-7y=-21 13x-7y=63

Mathematics
1 answer:
horrorfan [7]3 years ago
8 0

Answer:

y = 4

x= 7

Step-by-step explanation:

First you would rearrange the first equation x-7y=-21 and make x the subject:

x= -21 +7y

Then substitute x into the 2nd equation to find y:

13x - 7y= 63

13(-21+7y) - 7y = 63

-273 + 91y -7y = 63

-273 + 84y=63

84y = 63 + 273

84y = 336

y = 4

Once you have y you can substitute this into any of the original equations to find x, for example:

x - 7y = -21

x - 7(4) = -21

x - 28 = -21

x = -21 +28

x= 7

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A horse trot in a circle around it's trainer at the end of a 31 foot long rope. Find the area of the circle that is swept out. R
Mnenie [13.5K]
So, imagine the trainer is in the very middle of the circle and he is holding out a rope that's attached to the horse. The rope here from the trainer to the horse represents the radius of the circle. The horse trots around the trainer (middle point) in a circle.
The formula to find area of a circle is A = pi*r^2 (pi times r squared where r is radius)
We know that the radius of the "circle" here formed as the horse trots around the trainer is 31 (the 31 foot long rope). 
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3 0
3 years ago
Please helppppp
earnstyle [38]

Answer:

I think B

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Isn't it?

4 0
3 years ago
A brownie recipe calls for 1/2 cup of flour, 1/8 cup of cocoa powder, and 3/8 cup of sugar. How many cups of dry ingredients are
natka813 [3]

1/2 x 2= 1

1/8 x 2= 1/4

3/8 x 2= 3/4

3/4 x 1/4 = 3/16

3/16 x 1 = 3/16

YOUR ANSWER IS 3/16 dry ingredients

7 0
3 years ago
Solve the system by the substitution method.
Gemiola [76]

Answer:

(2,2)

Step-by-step explanation:

Given equations

x-3y=-4-------------------------------(1)

y=-3x+8.------------------------------(2)

Substitute 2 in 1. This means use the value of y in equation 1, to replace y

x-3(-3x+8)=-4------------------open brackets

x+9x-24=-4---------------------collect like terms

10x=-4+24

10x=20---------------------------divide by 10 both sides to get value of x

10x/10=20/10=2

x=2------------------------------use value of x in equation (2) to get value of y

y=-3x+8

y=-3(2)+8

y=-6+8=2

solutions

x=2, y=2

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3 years ago
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BabaBlast [244]
A) .10
b) 40x.35 = 14
5 0
3 years ago
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