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Homework Help: Math: Algebra: Distribution
The Distributive Property is an algebra property which is used to multiply a single term and two or more terms inside a set of parentheses. Take a
look at the problem below.
2(3 + 6)
Because the binomial "3 + 6" is in a set of parentheses, when following the Order of Operations, you must first find the answer
of 3 + 6, then multiply it by 2. This gives an answer of 18.
2(3 + 6)
2(9)
18
! Incorrect Method !
It would be incorrect to remove the parentheses and multiply 2 and 3 then
add 6, as this would give an incorrect answer of 12.
2(3 + 6)
2 * 3 + 6
6 + 6
12
Examine the expression below.
6(2+4x)
The two terms inside the parentheses cannot be added because they are not
like terms. Therefore, 2 + 4x, the expression inside the parentheses, cannot
be simplified any further. To simplify this multiplication, another method will
be needed. This is where the Distributive Property comes in.
Distributing a Number
We continue with the example presented at the end of the previous page.
6(2 + 4x)
The Distributive Property tells us that we can remove the parentheses
if the term that the polynomial is being multiplied by is distributed to, or
multiplied with each term inside the parentheses.
This definition is tough to understand without a good example, so observe
the example below carefully.
6(2 + 4x)
now by applying the Distributive Propery
6 * 2 + 6 * 4x
The parentheses are removed and each term from inside is multiplied by the six.
Now we can simplify the multiplication of the individual terms:
12 + 24x
Distributing a Negative Sign
The next problem does not have a number outside the parentheses,
only a negative sign.
-(3 + x2)
There are two easy ways to simplify this problem. The first and simplest
way is to change each positive or negative sign of the terms that were inside
the parentheses. Negative or minus signs become positive or plus signs.
Similarly, positive or plus signs become negative or minus signs. Recall that in the case
of 3, no positive or negative sign is shown, so a positive sign is assumed.
-3 - x2
We will now work through this problem again, but using a different method.
-(3 + x2)
Recall that any term that does not have a coefficient has an implied coefficient of
1. Because of the negative sign on the parentheses, we instead assume
a coefficient of negative one. Thus, we can rewrite the problem as
-1(3 + x2)
Now the -1 can be distributed to each term inside the parentheses as in
the first example in this lesson.
-1 * 3 + -1 * x2
-3 + -x2
Distributing Variables
A variable can be distributed into a set of parentheses just as we distributed
a negative sign or a number. Consider the following example.
x(y + 1)
We can now apply the distributive property to the expression by multiplying each
term inside the parentheses by x.
x * y + x * 1
Now simplifying the multiplication, we get a final answer of
xy + x
The same is true when a problem consists of a number, variables, and parentheses:
4x(x2 + 9)
Again, multiply each term inside the parentheses by the multiplier outside the parentheses.
4x * x2 + 4x * 9
Then simplify
4x3 + 36x
Homework Help: Math: Algebra
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