Solving Equations

Inverse operations

INVERSE = Opposite

• If I am solving an equation using inverses operations, I am solving it using opposite signs.

• Example: addition and subtraction are opposites.

• Multiplication and division are opposites.

WHEN CAN I USE INVERSE?

• When I have the following, I can use inverse operations:

• 9(a)=19 If there is no sign,

• A(9)=19 it means multiply.

• The opposite of multiply is divide, so divide the 2 numbers to find the value of the number.

When can I use inverse?

• N ÷ 9= 5 • The opposite of divide is multiply, so

you will find n by multiplying the two numbers.

• You can not use the inverse in division if the number comes before the letter like in

9 ÷ n = 45.

When Can I Use Inverse?

• N-3= 9

• The opposite of subtract is add, so I will add the 2 numbers to find N.

• With subtraction, I can only use inverse if the letter comes first.

• I cannot do 3-n=2 using inverse.

When can I use inverse?

• 9+n=10 or n+9=10

• The opposite of add is subtract, so subtract the smallest number from the largest to find your answer.

Division

• If the number comes first in division, I will divide to find my answer.

• Example 20÷n=5

• I will divide to find my answer.

Subtraction

• If the number comes first in subtraction, I will subtract to find the answer.

• Example:

• 12-n=3 n=12-3

Try some using inverse!!!

• n-9=10 What is n?

• 16+n=19 What is n?

• n÷5=9 What is n?

• n(5)=45 What is n?

• 12(n)=3 What is n?

Some more

• Practice 21.2