Transcript Notes

Solve and Write
2-Step Equations
What??? I just learned 1-step!
Relax. You’ll use what you already know
to solve 2-step equations.
Solving Two-Step Equations
To find the solution to an equation we must
isolate the variable. In other words, get the
variable on one side of the equation by
itself.
We isolate the variable by performing
operations that will eliminate (cancel) the
other numbers from the expression.
Solving Two-Step Equations
We have seen how to eliminate a constant
(Addition Property of Equality) & how to
eliminate a coefficient (Multiplication
Property of Equality).
What if an equation has both a constant
and a coefficient to be eliminated?
This is called a Two-Step Equation.
STEP 1
The first step will always be either adding or
subtracting. (Think: Order of Operations
backwards)
STEP 2
The second step will always be either
multiplying or dividing.
EX1) 8x + 5 = 61
-5 -5
This problem
has
multiplication,
so we need to
divide now.
8x =
8
x
=
56
8
7
This
problem has
addition, so
we need to
subtract
first.
Whatever
we do on
one side,
we have to
do on the
other.
Check
8x + 5 = 61
8(7) + 5 = 61
56+ 5 = 61
61= 61
EX2) 3a - 8 = 4
+8 +8
This problem
has
multiplication,
so we need to
divide now.
3a =
3
a =
12
3
4
This
problem has
subtraction,
so we need
to add first.
Check
3a - 8 = 4
3(4) - 8 = 4
12 - 8 = 4
4= 4
EX3) z + 2 = 26
6
-2 -2
z
6•
6
This problem
has division,
so we need to
multiply now.
=
z
This
problem has
addition, so
we need to
subtract
first.
24 • 6
= 144
Check
z + 2 = 26
6
144 + 2 = 26
6
24 + 2 = 26
26 = 26
EX4) m - 10 = 15
5 +10 +10
m
5•
5
This problem
has division,
so we need to
multiply now.
= 25 • 5
m = 125
This
problem has
subtraction,
so we need
to add first.
Check
m - 10 = 15
5
125 - 10 = 15
5
25 - 10 = 15
15= 15
Essential Question
When solving an equations, explain why it is
important to perform identical operations on
each side of the equal sign.
Date ______________
2-Step Equations
EX1) 8x + 5 = 61
EX2) 3a - 8 = 4
EX3) z + 2 = 26
6
EX4) m - 10 = 15
5
Essential Question
When solving an equations, explain why it is
important to perform identical operations on
each side of the equal sign.