Aim #35: How do we solve a
system of equations algebraically
using the Substitution Method?
(Unit 4 - Systems of Equations/Inequalities)
11-15-16
HW #35: Substitution Handout
Do Now: Solve the system of equation below graphically.
y=x-2
y + 4x = 13
Besides solving a system of equations GRAPHICALLY, we can solve a system of
equations algebraically using the SUBSTITUTION METHOD. Our goal is to
replace one variable with an equivalent expression containing the other variable,
so we can create a one-variable equation to solve.
Solving a System of Equations Algebraically
using Substitution
Ex #1:
y=x-2
y + 4x = 13
1) Write one equation
containing only one of the
variables by substituting an
equivalent expression
containing that variable.
2) Solve the equation.
3) Solve for the other
variable by substituting
into either original equation.
4) Check the solution into
both original equations.
Ex #2:
y + 1 = 3x
x=y-2
Ex #3:
3y + 2x = -1
-6x + y = 33
Ex #4:
3x + y = 5
3x + y = 8
Ex #5:
y = 2x - 4
-6x + 3y = -12
Ex #6:
x - 5 = 3y
y - 2x = 1
Ex #7:
5y + 3x = 20
x + 10y = 5
Unit 4 Quiz on Monday!
(Aims #34-37)