Graphing
When graphing a system of equations, the solution lies where the lines ______?
intersect
When do you use substitution?
When one equation is in standard form and one is in slope-intercept form.
You use elimination to solve a system when both equations are in what form?
Standard form
Bob is selling hats for $15 and t-shirts for $8. His goal is to make $250.
Write an equation to model the situation. Define variables.
15h + 8t = 250
t is the number of shirts and h is the number of hats
What does a system of linear equations with no solution look like on a graph?
parallel lines
DAILY DOUBLE: 400 points
When Lisa is 6 years old her sister was half her age. Now Lisa is 40, how old is her sister?
37 years old
Solve the system using elimination:
-7x - 2y=17
5x + 2y=-7
(-5,9)
Find the intercepts of
x+y = 20
(20,0) (0, 20)
What do linear equations look like on a graph if they have infinite solutions.
same line
Solve this system of equations using substitution:
-2x-5y=-14
y=6
(-8,6)
Solve the system using elimination:
-5x - 5y=10
-5x + 3y=18
(-3, 1)
Find the intercepts for
-3x + 2y =12
(0,6) and (-4,0)
How do you find the x-intercept in a standard form equation?
plug a 0 in for y.
Solve this system of equations by substitution:
y = x + 5
4x + 3y = -6
(-3,2)
Solve the system of equations using elimination:
9x - 3y=24
4x + 6y=-4
(2, -2)
Write a system if the sum of two numbers is 13 and the larger number is 1 more than 3 times the smaller number.
x+y =13
y = 3x+1
How do you find the y-intercept in a standard form equation?
plug a 0 in for x
Solve this system of equations by substitution:
y=5x - 2
-6x - 3y=-15
(1, 3)
Solve the system of equations using elimination:
-4x -2y=-18
3x +3y=12
(5, -1)
At the FHS basketball game hotdogs cost $2.50 and soda is $1.50 and they sold $170 for a total of 80 items.
Write a system. Define variables
1.50x + 2.50y = 170
x + y = 80
x is the number of sodas sold and y is the number of hotdogs sold