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44 votes
44 votes
Y = 3x + 3

y = x − 1
Explain how you will solve the pair of equations by substitution. Show all the steps and write the solution in (x, y) form.
I would like an expert answer please
and explain how it is done step by step

User Domgreen
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1 Answer

23 votes
23 votes

Answer:

(-2 , -3)

Explanation:

Systems of linear equations are pretty straight forward. You're looking for the intersection of your two lines. If you drew these two lines by using their slope and y-intercept, they would intersect at the point (-2 , -3). However, this isn't always a feasible option.

start with your first equation, y = 3x + 3

It helps that the variable y is already isolated on the equation because that would normally be your first step. (to isolate one of the variables)

Since y = 3x + 3 then I can SUBSTITUTE (3x + 3) into the other equation for y.

The second equation is y = x - 1

So instead of "y", I'm going to replace it with (3x + 3), making it

3x + 3 = x - 1

Now solve for x:

2x = -4

x = -2

Since you know what x equals, plug that in to either equation.

y = 3(-2) + 3

y = -6 + 3

y = -3

User Kstandell
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2.8k points