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3 votes
Given the system below,

9x+3y=-18
y=x+7
What is the ordered pair for the intersection
)?

User Titogeo
by
9.0k points

1 Answer

3 votes

Answer:

(-3.25,3.75)

Explanation:

Thuis can be answered with either of two approaches: Graphing and Matematical. We'll do both:

Graphing

Graph both equations. It is helpful to use a free online graphing utility: DESMOS.

The attached graph reveals the intersection of the lines at point (-3.25, 3.75).

Matematical

Solve the equations be using substitution. Rearrange either equation to isolate one of the two variables (x or y).

Lets use the second, since y is already isolated, making the task simple and fast. But the other equation could also be used, if desired.

y=x+7

Now use this expression of y in the other equation:

9x+3y=-18

9x+3(x+7)=-18

9x +3x +21 = -18

12x = -39

x = -(39/12)

x = -3 - (3/12)

x = -3.25

Now use x= -3.25 in either equation tand solve for y:

y=x+7

y=(-3.25)+7

y = 3.75

The solution to this series of equations is (-3.25,3.75)

Given the system below, 9x+3y=-18 y=x+7 What is the ordered pair for the intersection-example-1
User Notoria
by
7.8k points

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