Solving Equations by Using Substitution

Should you use the Substitution or Elimination method to solve this system of equations?

• Substitution

• Elimination

Should you use the Substitution or Elimination method to solve this system of equations?

• Substitution

• Elimination

Should you use the Substitution or Elimination method to solve this system of equations?

• Substitution

• Elimination

x = -3y - 8

x - 2y = -3

The above System is CURRENTLY setup to solve by:

• Substitution

• Elimination

• Graphing, Not Graphing...

  (aka Picturing the Graph)

  (aka Using graphing skills but not actually graphing)

• Infinite number of solutions

• (0, 7)

• (-5, -7)

• (5, 7)

• No Solution

• (2, 2)

• (-1, 2)

• (-1, -2)

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.

x = -3y - 8

x - 2y = -3

• (5, -1)

• (-5, 1)

• (-5,-1)

• (1,-5)

x = 3y -13

4x + 2y = 4

• (1, 4)

• (-1, -4)

• (-1, 4)

• (1, -4)

Solve:

y = -1x - 5

4x - 8y = 4

• (-3, -2)

• (5, -7)

• (3, 9)

• (-5, 4)