Use the following paragraph to answer Questions 1 and 2.

Question

Many gases make up Earth’s atmosphere, including nitrogen, oxygen, water vapor, argon, methane, and carbon dioxide. Carbon dioxide, water vapor, and methane have the ability to act like an insulator for the planet. Like the windows in a greenhouse, these greenhouse gases trap energy from the sun as heat in our atmosphere. Without their role in this greenhouse effect, Earth would be quite cold. Because of greenhouse gases, the surface of our planet averages around 59°F, making it the perfect place for life. Since about 1850, however, human activities have been releasing extra greenhouse gases into the air, particularly methane and carbon dioxide. Extra methane enters the atmosphere from livestock. Extra carbon dioxide enters the atmosphere by burning fossil fuels such as gasoline and coal for transportation and electricity production. Scientists think that this increase in greenhouse gases has slowly caused a rise in average temperatures across the Earth. Many scientists agree that the greenhouse gas contributing the most to the rise in average temperature is carbon dioxide.

Answer 1

1. What is the purpose of greenhouse gases in Earth's atmosphere?

Greenhouse gases act like an insulator for the planet, trapping energy from the sun as heat in our atmosphere.

2. What is causing an increase in greenhouse gases in Earth's atmosphere?

Human activities, particularly the burning of fossil fuels and the release of methane from livestock, are causing an increase in greenhouse gases in Earth's atmosphere.

Answer 2

Solve.

-8x-4y=4

-4x + 7y = 47

OA. (-3, 5)

OB. (-3,6)

OC. (-2,6)

OD. (5,-3)

Answer 3

We'll use substitution to solve this system of equations.

From the first equation:

-8x - 4y = 4

-4y = 8x + 4

y = -2x - 1

Now we'll substitute this expression for y into the second equation:

-4x + 7(-2x - 1) = 47

-4x - 14x - 7 = 47

-18x = 54

x = -3

Now that we know x = -3, we can substitute this value into either of the equations to find y:

-8(-3) - 4y = 4

24 - 4y = 4

-4y = -20

y = 5

Therefore, the solution is (-3,5), which is answer choice A.

Answer 4

What is the salutation to the system of equations?
Y=2x+4
Y=-x+1

A. (-2,0)
B.(-1,1)
C.(0,1)
D.(-1,2)

Answer 5

To solve for this system of equations, we can set them equal to each other and solve for x:

2x + 4 = -x + 1

3x = -3

x = -1

Now that we know x = -1, we can substitute this value into either of the equations to find y:

y = 2(-1) + 4

y = 2

Therefore, the solution is (-1,2), which is answer choice D.