Addition and Subtraction
Equations with Fractions
7-9
Jackie bought some almonds and ^1
8
lb of cashews.
She bought ^7
8
lb of nuts in all. How many pounds
of almonds did she buy?To find how many pounds of almonds, a,
write and solve the equation: a^1
8
^7
8
.a^1
8
^1
8
^7
8
^1
8
a^6
8
^3
4
Check by replacing awith ^3
4
. ^3
4
^1
8
^7
8
^6
8
^1
8
^7
8
^7
8
^7
8
TrueJackie bought ^3
4
lb of almonds.You can add a variable to both sides to solve an equation.^6
7
k^2
7
kis subtracted from ^67 .^6
7
kk^2
7
k Add kto both sides.^6
7
^2
7
k Simplify.^6
7
^2
7
^2
7
k^2
7
Subtract ^27 from both sides to isolate the variable.^4
7
k^2
7
^2
7
Use the Commutative Property of Addition to rewrite^27 kas k^27 .^4
7
k, or k^4
7
Study this example.w^3
5
^4
5
3 ^4
5
Simplify by adding the numbers on one side.w 1 ^2
5
3 ^4
5
w 1 ^2
5
1 ^2
5
3 ^4
5
1 ^2
5
Subtract 1^25 from both sides to isolate the variable.w 2 ^2
5
?
?
Think
Solve equations with fractions
the same way as equations
with whole numbers.Inverse Property of Addition
kk 0Let arepresent the weight of almonds.
Subtract ^18 from both sides
to isolate the variable.
Simplify.8206-2_238-239 10/7/07 11:29 AM Page 238