Download 1.10 - Applying Systems of Linear Equations

9/15/2015
1.10 - Applying Systems of
Linear Equations
Word Problems
Ex. 1:
The sum of two numbers is 4. The difference of the
same two numbers is 8. Find both numbers.
OBJECTIVE: TSW WRITE
THEIR OWN SYSTEM AND
DETERMINE THE BEST WAY
TO SOLVE THAT SYSTEM.
Step 1: Define your variables (you need 2):
x = first number
y = second number
SOLUTION: set up and solve:
x+y=4
x–y=8
Word Problems!
You Try…
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Ex. 2:
The sum of 5 times the first number and 7 times the
second number is 2. the sum of -2 times the first
number and 7 times the second number is 9. Find
both numbers.
SOLUTION: set up and solve…
5x + 7y = 2
-2x + 7y = 9
3. Find the value of two numbers if their sum is 12 and their
difference is 4.
SOLUTION:
x + y = 12
x–y=4
9/15/2015
4. Two shirts and one tie cost $42. One shirt and 2
ties cost $39.
SOLUTION: set up and solve…
2x + 1y = 42
1x + 2y = 39
5. At Los Betos you can get 2 tacos and 3 enchiladas
for $2.39 or 4 tacos and 5 enchiladas for $4.23.
What is the price of one taco and one enchilada?
SOLUTION: set up and solve…
2x + 3y = 2.39
4x + 5y = 4.23
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Homework
Worksheet
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