Exercise 9 Page 19

We want to find the sum and simplify the result of the addition. Let's look at the given expression! - 3/4+( - 1/3) When adding or subtracting fractions they should have the same denominator. In this case, we have two fractions with different denominators. Since 12 is a multiple of both 3 and 4, we can start by multiplying both the numerator and denominator of - 34 by 3 to create a common denominator.

-3/4+(- 1/3)

ExpandFrac

a/b=a * 3/b * 3

-3* 3/4* 3+(- 1/3)

Multiply

Multiply

-9/12+(- 1/3)

Next, we can multiply both the numerator and denominator of - 13 by 4 to create a common denominator.

-9/12+(- 1/3)

ExpandFrac

a/b=a * 4/b * 4

-9/12+(- 1* 4/3* 4)

IdPropMult

Identity Property of Multiplication

-9/12+(- 4/3* 4)

Multiply

Multiply

-9/12+(- 4/12)

Now, we can find the sum of two fractions with the same sign. Recall that we can do so by adding their absolute values. Let's do it!

|- 9/12|+|- 4/12|

AbsNeg

|-9/12|=9/12

9/12+|- 4/12|

AbsNeg

|-4/12|=4/12

9/12+4/12

AddFrac

Add fractions

9+4/12

AddTerms

Add terms

13/12

FracToMixed

Write fraction as a mixed number

1 112

Recall that both numbers are negative. This means that the sum is also a negative number, - 1 112.