Transcript Solve Equations with Multiplication and Division

Section 3.2
Solving Equations using Multiplication
and Division.
Solving Equations
Remember: to solve an equation, you
must isolate the variable and it must
have a coefficient of positive 1!
To isolate the variable, get rid of
everything around it by doing the
OPPOSITE action
1) Solve.
-5t = 60
To get the variable by itself, which
number needs to be moved?
-5
To move the -5, you have to do the
opposite operation. What operation
will we use?
division
1.
2.
3.
4.
1) Solve -5t = 60
-5 -5
Draw a vertical line to
t = -12
separate the equation
into 2 sides
Divide both sides by -5
Simplify
Check your answer
-5(-12) = 60
1.
2.
3.
4.
2) Solve 15 = 6n
6
6
Draw a vertical line
Divide both sides by 6
2.5 = n
Simplify
Check your answer
15 = 6(2.5)
3) Solve -3v = -129
1.
2.
3.
4.
v = -126
v = -43
v = 43
v = 126
Answer Now
x
 12
4) Solve
4
You don’t like fractions? Let’s get rid of
them! 
“Clear the fraction”
by multiplying both sides of the equation
by the denominator.
1.
2.
3.
4.
x
4) Solve  12
4
Draw a vertical line
x
Clear the fraction –
4 ·  12 · 4
multiply both sides by 4
4
Simplify
Check your answer
x = -48
48
 12
4
1.
2.
2x
5) Solve
= 18
3
2x
3·
= 18 · 3
Draw a vertical line
3
Clear the fraction –
3.
4.
5.
6.
multiply both sides by 3
Simplify
Divide both sides by 2
Simplify
Check your answer
2x = 54
2
2
x = 27
2(27)
 18
3
6) Which step clears the fraction in
3b
 12
5
1.
2.
3.
4.
Multiply by 3
Multiply by 5
Multiply by -12
Multiply by -5
Answer Now
7) Solve
1.
2.
3.
4.
b = -56
b = -14
b = 14
b = 56
Answer Now
4b
 8
7
9/11/13
Homework:
Workbook page 19