8n=16
What is a LINEAR equation?
An equation that when graphed, creates a straight line.
How many solutions are represented in the graph?
1 solution
What does the word "substitute" mean?
To exchange/trade/etc.
How many solutions can a system of linear equations have?
one, none/zero, or infinitely many solutions
Julie is 3 years older than her sister. Julie's age is 11. How old is Julie's sister?
s + 3 = 11 (Julie is 3 years older than her sister)
s = 8
Her sister is 8 years old
Alison
3p+8=35
p=9
True or False:
It does not matter which method you use when solving systems of linear equations because they will all give you the same answer.
True
14) What is the solution to the system of linear equations?
(2,2)
What is the first step when solving a system of linear equations using the SUBSTITUTION method?
Isolate the variable
How many solutions will a set of parallel lines have?
Zero
We are at a Seattle Seahawks game. We buy 4 hotdogs and 1 drink. We spend a total of $17. If the drink costs $5, how much does one hotdog cost?
4h + 5 = 17
4h = 12
h = 3 (One hotdog costs $3)
4x+27=-x+42
x=3
What does it mean to "find the solution" to a system of linear equations?
It means to find the point (x and y value of) where the 2 lines intersect.
Solve by graphing:
y=-2x+5
y=3x
(1, 3)
y=4x
2x-y=5
What is the next step in solving the above system of equations?
2x-(4x)=5
Combine like terms (& solve for x).
What is the solution to the system of equations?
y=-2/3x+6
y=6-4/6x
Infinitely many solutions
Find the value of two numbers if their sum is 12 and their difference is 4.
4 and 8
3h+2+9-h=110-9h
h=9
At least how many linear equations will be in a system of linear equations?
At least 2 linear equations
Solve by graphing:
y=1/2x -5
y=x+1
(-12, -11)
Use the substitution method to solve the system of linear equations:
y=2x
3x+y=20
Solution: (4,8)
How many solutions are there for the following system of linear equations? If there is only one solution, what is the solution?
y = 4x + 2x + 1
y = 8x - 9
One solution; (5, 31)
The school that Stefan goes to is selling tickets to a choral performance. On the first day of ticket sales the school sold 3 senior citizen tickets and 1 child ticket for a total of $38. The school took in $52 on the second day by selling 3 senior citizen tickets and 2 child tickets. Find the price of a senior citizen ticket and the price of a child ticket.
senior citizen ticket: $8, child ticket: $14
-5(a+3)+6(a+1)+8a=9(a-1)
Infinitely Many Solutions
So far we have learned 2 different methods for solving systems of linear equations. What are they?
Graphing and substitution
Solve by graphing:
y=2/3x+6
2x+3y=12
(-1.5, 5)
Use the substitution method to solve the system of linear equations:
2x+3y=13
y=x+1
(2, 3)
How many solutions does this system of linear equations have?
y=-2/3x+6
2x+3y=12
No Solution
Mrs. Pastala tells you that the next test is worth 122 points and contains 38 problems. Multiple-choice questions are worth 3 points and word problems are worth 4 points. How many of each type of questions are in there?
8 word problems
30 Multiple Choice