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
True
Jackie 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 0
Let arepresent the weight of almonds.
Subtract ^18 from both sides
to isolate the variable.
Simplify.
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