Download Solving Two-Step Equations: It is called a two

Solving Two-Step
Equations
Integer Review
Adding and Subtracting
Think Money
 Think Temperature

-18 + 13
-5
-11 + 19
8
41 + (-63)
-22
Integer Review
Multiplication/Division
+
-
-4(11)
-44
Think
Christmas
Tree
-
-8(-6)
48
6(-5)
-30
Brain Break
Why you should like equations

To solve an equation, you “undo” or do the
opposite of what is told to you.
3x + 7 = 19
 The problem says, multiply by 3, add 7
 You being in middle school say “NO WAY”
subtract 7, divide by 3


Opposite and backwards – just like most
14 year olds
Solving Two-Step Equations:
2x + 5 = 19
- 5 - 5
2x
= 14
2x
2
= 14
2
x
= 7
It is called a two-step
equation because it takes
two steps to solve it
“Undo” the addition
first
“Undo” the implied
multiplication last
The variable is by
itself so the problem
is completed
Solving Two-Step Equations:
3 – a = 9
7
-3
- 3
-a = 6
7
7(-a) =(6) 7
7
-a = 42
a = -42
It is called a two-step
equation because it takes
two steps to solve it
“Undo” the +3 first
“Undo” the implied
division last
The variable is by
itself so the problem
is completed
Solving Two-Step Equations Practice:
4 + 2y = 10
- 4
- 4
2y = 6
x – 6 = -12
8
+6 = +6
2y = 6
2
2
x
8
y = 3
8(x)
8
= -6
= (-6) 8
x = -48
Solving Two-Step Equations Practice:
-10 + 2y = 12
+10
+10
2y = 22
2y = 22
2
2
x = 11
9z + 4 – 8 = 5.4
5
+8
+8
9z + 4 = 13.4
5 Multiply by
5
9z + 4 = 67
Add 4
9z = 63
Divide by 9
z = 7
Solving Two-Step Equations
Practice:
4(17 – x =
) (-10 )4
4
17 – x = -40
-17
= -17
-x = -57
x = 57
0.2y – 3 = 12
+ 3
+3
0.2y = 15
0.2y = 15
0.2
0.2
y = 75
Find a Match Activity
You and your 11 o’clock partner will need to:



Obtain a “find a match” paper
Work out the problems on the paper
Go around the room to find the words that match
the numbers you have
Homework: worksheet 100
ON YOUR OWN!