Linear combination with word problems
Ordering SoftballsYou are ordering softballs for two softball leagues.
The Pony League uses 11-inch softballs priced at $2.75. The Junior
League uses 12-inch softballs priced at $3.25. The bill smeared in the
rain, but you know the total was 80 softballs for $245. How many
of each size did you order?
Title: Mar 1­8:12 AM (1 of 4)
Extra Credit Problem
Set up equations and solve (show work use the method we are doing in
class to get credit)
Mr. Solak tells you that next week's test is worth 100 points
and contains 38 problems. Each problem is worth either 5 points
or 2 points. Because you are studying systems of linear equations,
Mr. Solak says that for extra credit you can figure out how many
problems of each value are on the test.
(
Let x = 2 point problems
let y = 5 point problems
(
x + y = 38 -2
2x + 5y = 100
-2x + -2y = - 76
3y = 24
x + 8 = 38
-8
-8
x = 30
Title: Mar 1­8:07 AM (2 of 4)
3
3
y=8
The Substitution Method for solving systems
Substitution Method is a useful method when
one of the variables has a coefficient of 1.
Procedure - - 1) Solve one of the equations for one of its variables
2) Substitute the (expression) from step 1 into the other equation and solve for the other
variable.
3) Substitute the value from Step 2 into the revised equation from Step 1 and solve.
Ex 1) Solve the system
-x + y = 1
Title: Mar 1­8:15 AM (3 of 4)
2x + y = -2
Ex 2) Same directions as before
2x + 2y = 3
x - 4y = -1
Assignment Page 408, #'s 6 - 13
Title: Mar 1­8:25 AM (4 of 4)