Using Both Substitution

1
Lesson 76

• Using Both Substitution
• Elimination

2
Using Both Substitution and Elimination

• Solve for one variable in one equation and plug
  it into the other two equations, then use
  elimination to solve.
• x 3y
• x y z 56
• x 2y 3z -25

3
Plug 3y in for x into the second and third
equations.
4

• Dont forget to solve for
• the other variables
• 11 3z -25
• z 12
• x 3(11)
• x 33
• x 33, y 11, z 12

5

• Solve equation (c) for x.
• Replace x with 3z

6
Your Turn
7
Try From the Worksheet

• 1

8
WIR 76