2.40 Solving Systems of Equations

What is the solution to the system?

• (0, 3)
• (1, -1)
• (-3, 1)
• (1, 3)

When you graph the exact same equation twice,

• you will have no solution. 
• you will have one solution.
• you will have infinite solutions. 
• you will graph a giraffe. 

This system has _____ solutions

• 0
• 1
• 2
• Infinitely many

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.

Solve the system by substitution.
 
5x + 4y= −14
y =  −7x  −  15 

• (-2, -1)
• (1, -2)
• (-2, 1)
• (-1, -2)

Solve the system by substitution.

x + 2y = 2

x = -4y + 2

• (-3, 0)
• (0, 2)
• (-3, -2)
• (2, 0)

Solve the system by substitution.

y = -6x + 5

-2x + y = 5

• (-3, -6)
• (-6, 3)
• (0, 5)
• (-3, 5)

Solve the system by substitution.

6x + y = -1

y = -3x - 4

• (3, 1)
• (1, 7)
• (-3, 1)
• (1, -7)

Solve by elimination:
4x+9y=28
-4x-y=-28

• (-7,0)
• (6,0)
• (-6,0)
• (7,0)

Solve by elimination:

3x+7y=23

-3x-7y=-17

• No solution

• (0, 3)

• (-3,3)

• (3,3)