2.5b Solving Systems by Substitution

One equation is already isolated. Which choice shows the correct substitution?

2x − 3y = −1

y = x − 1

• 2x − 3(x − 1) = −1

• 2(x - 1) - 3y = -1

• 2x − 3y = x − 1

• y = 2x - 3y

Solve for x:

2x - 3(x - 1) = -1

• x = -4

• x = 2

• x = -2

• x = 4

If x = 4, solve for y:

2x - 3y = -1

y = x - 1

• y = 3

• y = 5

• y = -3

• y = -5

Since x = 4 and y = 3, the solution is:

• (3, 4)

• (4, 3)

What does a One Solution system look like on a graph?

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How many solutions does this system of equations have?

• No solution

• One Solution

• Infinite Solutions

How many solutions does this system of equations have?

• No solution

• One solution

• Infinite solutions

1. Solve the following system for x:

y = 6x − 11

−2x − 3y = −7

• x = 1

• x = 3

• x = 2

• x = 5