Solving a system of equations

How confident are you are solving a system of equations using substitution?

• I am rock SOLID!

• I am probably ok, but a few more examples wouldn't hurt.

• I still have a lot of questions.

• I will need help walking through that again.

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

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

• solve for x

• solve for y

• solve for the slope

• find the y-intercept

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

• solve for x

• solve for y

• solve for the slope

• find the y-intercept

Solve the following system of equations using substitution.

y=x+3

x+y=9

• (2,5)

• (3,6)

• (4,7)

• IMS

Solve the system of equations using substitution:
y = 2x + 5
2x + 2y = 4

• (1, 7)
• (7, 1)
• (2, 9)
• (-1, 3)

Solve the system by substitution. 
y = 2x − 11 
2x − 8y = 4 

•  (6, 1)
• (6, −4)
• (6, −1)
• Infinite number of solutions  

Solve this system of equations.

y = 2x + 1

y = 4x - 1

• (1,3)

• (-1,-3)

• (-1,3)

• (3,1)

Solve the system by substitution. 
3x − 2y = 7 
y = 2x − 7 

• No solution 
•  (7, 7)  
•  (−7, −7)  
•  (−7, −3)  

The solution (x, y) to a system of equations is the point where they the lines

• Run off the graph

• Don't touch

• Intersect

• Exist