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2 years ago

Y=4x and 3x+y=-21. Substitute

Mathematics

1 answer:

gizmo_the_mogwai [7]2 years ago

5 0

value of x= -3 and value of y = -12

Solution set is (-3,-12)

Step-by-step explanation:

We need to solve the system of equations using substitution

The system of equations are:

$y=4x\\3x+y=-21$

Solving:

Let

$y=4x\,\,eq(1)\\3x+y=-21\,\,eq(2)$

Solving:

Putting value of y from equation 1 into equation 2

$3x+y=-21\\3x+4x=-21\\7x=-21\\x=-21/7\\x=-3$

So, value of x = -3

Now, putting value of x into equation 1 and find value of y

$y=4x\\y=4(-3)\\y=-12$

Value of y = -12

So, value of x= -3 and value of y = -12

Solution set is (-3,-12)

Keywords: System of equations

Learn more about system of equations at:

#learnwithBrainly

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Let c = 10.Which expression makes the comparison true.

den301095 [7]

Answer:

c² - 63

Step-by-step explanation:

4c - 10 = 30

3c ÷ 3 = 10

c² - 63 = 37

c² ÷ 10 = 10

Since c² - 63 = 37 and c + 25 = 35, 37 is greater than 35 so it would make sense to choose c² - 63 as the answer.

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2 years ago

Which statement describes how to determine if a relation given in a table is a function?

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Answer: B

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melisa1 [442]

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2 years ago

For the quadratic relation y = -3x2 - 7x + 8,

Varvara68 [4.7K]

Answer:

a) y-int is at (0, 8)

b) zeros are at (0.8, 0) and (-3.2, 0); after having rounded to the nearest tenth.

Step-by-step explanation:

Given that y = -3x² - 7x + 8

we can find our y-intercept by setting x = 0

y = -3 (0)² - 7 (0) + 8

y = 8

so, our y intercept is at (8, 0)

To find our zeros, or x-intercepts, we need to set y = 0

0 = -3x² - 7x + 8

Let's use the quadratic formula

x = (-b ± √(b² - 4 (a * c))) / 2a

where, in this case

a = -3

b = -7

c = 8

x = (7 ± √((-7)² - 4 (-3 * 8))) / (2 * -3)

x = (7 ± √(49 - -96) / -6

x = (7 ± √145) / -6

using the addition pathway

x = (7 + √145) / -6

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using the subtraction pathway

x = (7 - √145) / -6

x = -0.8

So, our x-intercepts, or zeros, will lie on the points

(0.8, 0) and (-3.2, 0)

Create a table of x and y values using the given equation, and plot and graph. Clearly label your y and x intercepts.

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(1, -2)

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aev [14]

Answer:

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