Transcript Solving Two-Step Equations

Solving Two-Step
Equations
Day Two
Ms. Turk, Algebra I
Unit 2-2

x

2
Example 1
4
10
Hint: As your first step, multiply each side
by the denominator of the fraction.
(10)
x2
 4 (10)
10
X + 2 = 40
-2 -2
x = 38
• Multiply each side of
the equation by 10.
• Subtract 2 from both
sides of the equation.
• Simplify.
x3
Example 2
 12
7
Hint: As your first step, multiply each side
by the denominator of the fraction.
(7)

x3
 12 (7)
7
X - 3 = 84
+3 +3
x = 87
• Multiply each side of
the equation by 7.
• Add 3 to both sides of
the equation.
• Simplify.
Example 3
Try one on your own!

x 5
2
8
Hint: As your first step, multiply each side
by the denominator of the fraction.
(8)
x 5
 2 (8)
8
x - 5 = 16
+5 +5
x = 21
• Multiply each side of
the equation by 8.
• Add 5 to both sides of
the equation.
• Simplify.
Reciprocals
• How do I find the •
reciprocal of a
number?
• Here are some
examples. Write
them down!
If it’s a fraction, flip it.
If it’s an integer, put 1
over that integer.
5
8
3
8
5
1
3
Reciprocals
• What happens when
you multiply a number
by its reciprocal?
• Another example…
Let’s multiply 8 by its
reciprocal. How do
you write 8
as a 
fraction?

3 4 12
  1
4 3 12
8 1 8
  1
1 8 8
3
Using Reciprocals to
x 2  7
Solve Problems 4
3
• Add 2 to both sides.
x 9
4
4 
• Multiply both
sides by 4 3
x 9
the reciprocal of the
coefficient.

• 1x is the same as x,
and the fraction
reduces to 12.

 
3 4
36
1x 
3
x = 12
 
3 
Using Reciprocals to Solve
Problems
2
 x  39
3
2
 x 6
3
 3  2
 3 
  x  6 
 2  3
 2 



18
1x 
2
x = -9
Using Reciprocals to Solve
Problems
Now you try!
2
x  10
5
5 2
5 
  x  10 
2 5
2 



2
x46
5
50
1x 
2
x = 25
Classwork
Workbook page 22
9, 10, 11, 13 - 31
odd
Show your work!