Aim #23: How do we solve a system of equationsalgebraically using the
substitution method?
10-24-16
Homework: Handout
Do Now: Consider the two system of equations below. Verify whether the
given ordered pairs are solutions:
(3,4)
(2, 2.4)
y=x+1
4x + 5y = 20
y = -2x + 10
2x + 6y = 10
{
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Besides solving a system of equations GRAPHICALLY, another method is the
SUBSTITUTION METHOD. By replacing one variable with an equivalent
expression containing the other variable, you can create a one-variable equation
to solve.
Example 1: y = 2x + 1
x-y=7
Example 2:
2x + y = 4
2x + 3y = 9
Check your solution!
Check your solution!
HW #22 Solutions: (p. 189 #s 14-21).
No Solution
No Solution
All ordered pairs that lie on the graph of 2y = 4x ­ 6.
Solve and check each system algebraically using substitution.
a)
y = 4x - 1
y=- 1 x+8
2
c)
y = 2x - 4
-6x + 3y = -12
b)
d)
3x + y = 5
3x + y = 8
y = -x + 6
3
y= x -3
4
e)
y = 0.2x + 10
4x + 5y = 35
f)
4x + 3y = 27
y = 2x - 1
g) Is (-2,-7) the solution of the following system? Explain.
7y - 4x = 29
x = y -5
Sum it Up!
To determine the solution to a system of equations, we have found the solutions
____________ and ____________ using ____________.
How can you verify the solution to a system of equations?