Systems by Substitution

Use substitution to solve the system of equations.

5x + y = –24

x + 3y = –2

• x = –5

  y = –1

• x = 5

  y = 1

• x = –5

  y = 1

• x = 5

  y = –1

Use substitution to solve the system of equations. How many solutions are there?

(1/2)x − (1/3)y = 5

x = (2/3)y + 10

• There are no solutions.

• There is one solution.

• There are infinitely many solutions.

• It is not possible to determine the number of solutions.

Use substitution to solve the system of equations.

y = 4.5x + 7.5

y = –3.5x – 4.5

• x = –1.5, y = –0.75

• x = 1.5, y = 0.75

• x = –1.5, y = 0.75

• x = 1.5, y = –0.75

When using substitution to solve a system of equations, you tell when a system has no solution when the resulting equation is always false as in this example 4=5.

• True

• False

• Both True and False

• I don't have a clue.

Tickets to a school play cost $3 for students and $8 for adults. On opening night, $1,000 was collected and 150 tickets sold. Use substitution to solve a system of equations to find how many of each kind of ticket were sold?

• 40 student tickets

  110 adult tickets

• 110 student tickets

  40 adult tickets

• 50 student tickets

  100 adult tickets

• 100 student tickets

  50 adult tickets

Solve this system of equations
y=8x-5
y=2x+19

• (1,3)
• (2.4, 23.8)
• (2.5,15)
• (4,27)

Solve this system of equations
2x+y=9
y=5x+2

• (1,7)
• (2,5)
• (-1,-3)
• (5,-1)

y = -2x + 18
y = 8

• (5, 8)
• (-5, 8)
• (2, 8)
• (-2, 8)

The equations of two lines are:
 2x-y=4 and y=-2x+8.
What is the value of x in the solution for this system?

• x=8
• x=3
• x=11
• x=5

What is the solution to this system?
y= 4x + 3
2x - 3y = 21

• (3,-9)
• (-3,-9)
• (-3,9)
• (0,1)