Transcript 6-3 solving systems using elimination

WARM UP
Complete the statements with one solution, no solution, or
infinitely many solutions.
1. If 2 linear equations have the same slope, they have
.
2. If 2 linear equations have the same slope and same yintercept, they have
.
3. If 2 linear equations have the different slopes, they
have
.
ADDING OR SUBTRACTING EQUATIONS
When both linear equations of a system are in the form Ax + By = C you
can solve the system using elimination.
5x – 6y = -32
3x + 6y = 48
BASKETBALL
292 tickets were sold for a high school basketball
game. An adult ticket costs $3 and a student ticket
costs $1. Ticket sales were $470. Use a system of
linear equations to find the number of each type of
ticket sold.
EXAMPLE
Should you add or subtract to solve?
a. a – b = 8
a + 2b = 5
b. -3x +2y = 1
4x – 2y = -3
c. m + t = 6
5m + t = 14
SALES
Suppose your class receives $1084 for selling 205 packages of
greeting cards and gift wrap. Let w = the number of packages of
gift wrap sold and c = the number of packages of greeting cards
sold. Use a system of equations to find the number of each type of
package sold.
PLAN A STRATEGY…
Can I
eliminate a
variable by
adding or
subtracting?
yes
Do it.
yes
no
Can I multiply one of
the equations by a
number, and then add no
or subtract the
equation?
Do it.
Multiply both
equations by
different
numbers. Then
add or subtract
the equation.
WORK WITH A PARTNER…
Suppose you want to solve this
3x – 2y = 6
system using elimination.
5x + 7y = 41
a. What would you multiply each equation by to eliminate x?
b. What would you multiply each equation by to eliminate y?
c. Solve the system using elimination. Be sure to check your
solution!
HOMEWORK
Pg 282-283 # 11 – 25 odd