1.3 2-Step Equations
You are trying to find the value of x which
makes this equation true (equal).


How can you do this?
4x + 12 = 15
make both sides zero
 get x alone
 get 12 alone
How would you get
x alone?
You need to get x alone on one side of the
equal sign. 
4x + 12 = 15
 use inverse (opposite)
     operations
multiply by zero
 add x to each term
Use inverse (opposite) operations to get x alone.

Which numbers
need to
be cancelled  out
to get x alone?
4x + 12 = 15
 4 and 15
4 and 12
12 and 15
The term farthest
from x needs to
be cancelled
out first.

4 and 12 need to be cancelled out to get x alone.
4x + 12 = 15
Which term is farthest from x?
 12
4
What would you do to BOTH
sides of the equation to cancel out +12 ?
4x + 12 = 15
add 12
multiply 12
divide 12
subtract 12
Subtract 12 from
both sides.

What will
the equation
look like now?

4x +  12   =   15
-  12
4x = 27
4x + 24 = 3
4x = 3
- 12
What would you cancel next to get x alone?
4x +  12   =   15
3

4x           =   3
-  12
OR
- 12
4
*
Cancel out the
4 to get x alone


What would you do
to BOTH sides of the
equation to cancel out
4 (times four)?
4x = 3
add 4
multiply 4
divide 4
subtract 4
What does x equal?
4x = 3
4
4
4/3
-1
3/4
 12
x = 3/4
4x = 3
4
4
Plug in (substitute) 3/4 for x to check your solution.
    (the equation will be equal if 3/4 is correct)
4     +12 = 15
4  + 12 = 15
(¾)
x
Your solution
What number is three-fourths of four
       +12 = 15
4     +12 = 15
4  + 12 = 15
(¾)
x
?
Since x = ¾ makes the equation equal (15 =15),
         x = ¾ is the correct answer.
3 + 12 = 15
15  =  15
The
n
d
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