Solve for Y Systems of Equations

Which answer has a correct first step for this system:

• The variable is already isolated, so we've already solved the system.

• The variable is already isolated for y, so we substitute it in the first equation and solve for x

  3x + 3(3x + 5) = 3

• Free sha vaca doo

• The variable is already isolated for y, so we substitute it in the second equation and solve for x

  y = 3(3x + 3y) = 3

Solve this system using substitution

y = 3x - 5

2x + 4y = -6

• (1, -2)

• (2, -2)

• (1, 2)

• Why have you done this?

Solve with substitution

x = -3y - 8

x - 2y = -3

• (5, -1)

• (-5, 1)

• (-5,-1)

• (1,-5)

What does
"solution to a system of equations"
mean?

• It's the point where both equations equal zero

• It's the point where graphs of both equations cross the y-axis

• It's the point that solves both equations at the same time

• It's the point where graphs of both equations cross the x-axis

 4x + 8y = 20
-4x + 2y = -30

• (-7,1)

• (2,-5)

• (-2,5)

• (7,-1)

How many solutions will this system have? 

• No solution

• One Solution

• I Don't Know

• Infinitely Many Solutions

Solve for x and y
y = 2x + 1
y = 4x - 1

• (1,3)

• (-1,-3)

• (-1,3)

• (3,1)

Solve the system given:
3x - y = 7
2x + y = 3

• (-1,2)

• (5,4)

• (4,5)

• (2,-1)

What is the first step in solving a system by Substitution?

• Make sure both equations are in standard form.

• Make sure at least one equation is solved for one variable.

• Make sure both equations are in slope-intercept form.

• Make sure both equations can be solved.

The first step in solving using the substitution method is __________.

• get x by itself

• get y by itself

• get either variable by itself

• add the equations together