Algebra 1 : Distributive Property

Study concepts, example questions & explanations for Algebra 1

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Example Questions

Example Question #151 : How To Use Foil In The Distributive Property

Multiply and simplify:

\(\displaystyle (4x- 7) (2x-5)\)

Possible Answers:

\(\displaystyle 8x^{2} -6x + 35\)

None of the other responses gives the correct answer.

\(\displaystyle 8x^{2} -34x - 35\)

\(\displaystyle 8x^{2} -6x - 35\)

\(\displaystyle 8x^{2} -34x + 35\)

Correct answer:

\(\displaystyle 8x^{2} -34x + 35\)

Explanation:

Using the FOIL method, find the following four products:

F (product of the first terms): \(\displaystyle 4x \cdot 2x = 8x^{2}\)

O (product of the outer  terms): \(\displaystyle 4x \cdot (-5) = -20x\)

I (product of the inner terms): \(\displaystyle - 7 \cdot 2x = -14x\)

L (product of the last terms):  \(\displaystyle - 7 \cdot (-5) = 35\)

Add the terms and simplify:

\(\displaystyle 8x^{2} + (-20x )+ (-14x ) + 35\)

\(\displaystyle = 8x^{2} -34x + 35\),

the correct choice.

Example Question #152 : How To Use Foil In The Distributive Property

Simplify:  \(\displaystyle (2x-3)(x+4)\)

Possible Answers:

\(\displaystyle 2x^2+5x-12\)

\(\displaystyle 2x^2-5x-12\)

 \(\displaystyle 2x^2+5x+12\)

\(\displaystyle 2x^2+10x-12\)

\(\displaystyle 2x^2+3x-12\)

Correct answer:

\(\displaystyle 2x^2+5x-12\)

Explanation:

In order to solve this, use the FOIL method to distribute the terms.

\(\displaystyle (2x-3)(x+4) =(2x)(x)+(2x)(4)+(-3)(x)+(-3)(4)\)

Simplify the terms.

\(\displaystyle 2x^2+8x-3x-12\)

Combine like-terms.

The answer is:  \(\displaystyle 2x^2+5x-12\)

Example Question #151 : Distributive Property

Simplify: \(\displaystyle (2x-1)(x+4)\)

Possible Answers:

\(\displaystyle 2x^2-9x-4\)

\(\displaystyle 2x^2-4\)

\(\displaystyle 2x^2+9x+4\)

\(\displaystyle 2x^2+7x-4\)

Correct answer:

\(\displaystyle 2x^2+7x-4\)

Explanation:

Use the FOIL method to distribute:

First: \(\displaystyle 2x \cdot x=2x^2\)

Outer: \(\displaystyle 2x \cdot 4=8x\)

Inner: \(\displaystyle -1 \cdot x = -x\)

Last: \(\displaystyle -1 \cdot 4 = -4\)

Then simply combine like terms.

Example Question #154 : How To Use Foil In The Distributive Property

Simplify: \(\displaystyle (3x-2)(4x-1)\)

Possible Answers:

\(\displaystyle 7x^2-11x+2\)

\(\displaystyle 12x^2+11x-2\)

\(\displaystyle 7x^2+11x-2\)

\(\displaystyle 12x^2-11x+2\)

\(\displaystyle 3x^2-11x+2\)

Correct answer:

\(\displaystyle 12x^2-11x+2\)

Explanation:

Use the FOIL method to distribute:

First: \(\displaystyle 3x \cdot 4x = 12x\)

Outer: \(\displaystyle 3x \cdot (-1)=-3x\)

Inner: \(\displaystyle -2 \cdot 4x = -8x\)

Last: \(\displaystyle -2 \cdot (-1) = +2\)

Then simply combine like terms.

Example Question #155 : How To Use Foil In The Distributive Property

Simplify: \(\displaystyle (3x+5)^2\)

Possible Answers:

\(\displaystyle 9x^2+15x+25\)

\(\displaystyle 9x^2+25\)

\(\displaystyle 9x^2-25\)

\(\displaystyle 9x^2+30x+25\)

\(\displaystyle 6x^2+10\)

Correct answer:

\(\displaystyle 9x^2+30x+25\)

Explanation:

Use the FOIL method to distribute:

First: \(\displaystyle 3x \cdot 3x=9x^2\)

Outer: \(\displaystyle 3x \cdot 5=15x\)

Inner: \(\displaystyle 5 \cdot 3x = 15x\)

Last: \(\displaystyle 5 \cdot 5 = +25\)

Then simply combine like terms.

This is also a common pattern (squaring a binomial) with which you should be familiar.

Watch for the common mistake of squaring the terms individually and leaving out the \(\displaystyle +30x\).

Example Question #156 : How To Use Foil In The Distributive Property

Use the FOIL method to simplify:  \(\displaystyle (x+6)(x-12)\)

Possible Answers:

\(\displaystyle x^2+6x-72\)

\(\displaystyle x^2-6x-72\)

\(\displaystyle x^2+6x-6\)

\(\displaystyle x^2-72\)

\(\displaystyle x^2-6x-6\)

Correct answer:

\(\displaystyle x^2-6x-72\)

Explanation:

Multiply the first term of the first binomial with both terms of the second binomial.  Then add the second term of the first binomial multiplied with both terms of the second binomial.

\(\displaystyle (x+6)(x-12) = (x)(x)+(x)(-12)+(6)(x)+(6)(-12)\)

Simplify the terms.

\(\displaystyle x^2-12x+6x-72\)

Combine like-terms.

The answer is:  \(\displaystyle x^2-6x-72\)

Example Question #157 : How To Use Foil In The Distributive Property

Distribute the product using the FOIL method. 

\(\displaystyle (2x+y)(3x-4y)\)

 

Possible Answers:

\(\displaystyle 2x^2+5xy-y^2\)

\(\displaystyle 6x^2-5xy-4y^2\)

\(\displaystyle 6x^2+11xy+4y^2\)

\(\displaystyle 3x^2-11xy+4y^2\)

Correct answer:

\(\displaystyle 6x^2-5xy-4y^2\)

Explanation:

The FOIL method stands for FIRST, OUTER, INNER, LAST. It refers to the terms in the pair of parenthesis. 

We multiply together the

FIRST TERMS: \(\displaystyle 2x*3x=6x^2\)

OUTER TERMS: \(\displaystyle 2x*(-4y)=-8xy\)

INNER TERMS: \(\displaystyle y*3x =3xy\)

LAST TERMS: \(\displaystyle y*(-4y)=-4y^2\)

Adding them up and combining like terms yields 

\(\displaystyle 6x^2-5xy-4y^2\)

Example Question #158 : How To Use Foil In The Distributive Property

Simplify the binomials:  \(\displaystyle (x+9)(2x-3)\)

Possible Answers:

\(\displaystyle 2x^2+8x-12\)

\(\displaystyle 21x-27\)

\(\displaystyle 2x^2-15x-27\)

\(\displaystyle 2x^2+6x-12\)

\(\displaystyle 2x^2+15x-27\)

Correct answer:

\(\displaystyle 2x^2+15x-27\)

Explanation:

The FOIL method to multiply binomials is:

\(\displaystyle (a+b)(c+d) = ac+ad+bc+bd\)

Multiply the given problem using this format.

\(\displaystyle (x+9)(2x-3) = (x)(2x)+(x)(-3)+(9)(2x)+(9)(-3)\)

Simplify the right side.

\(\displaystyle 2x^2-3x+18x-27\)

Combine like-terms.

The answer is:  \(\displaystyle 2x^2+15x-27\)

Example Question #159 : How To Use Foil In The Distributive Property

Simplify the following expression:

\(\displaystyle (x+1)(2x-1)\)

Possible Answers:

\(\displaystyle 2x^2+x+1\)

\(\displaystyle 2x^2+x-1\)

\(\displaystyle 2x^2+3x-1\)

\(\displaystyle 2x^2+x\)

\(\displaystyle 2x^2+3x+1\)

Correct answer:

\(\displaystyle 2x^2+x-1\)

Explanation:

To simply this expression you must distribute correctly.

Using the FOIL method is the easiest wait to do this, so:

FIRST: \(\displaystyle x*2x=2x^2\)

OUTTER: \(\displaystyle x*-1=-x\)
INNER: \(\displaystyle 2x*1=2x\)
LAST: \(\displaystyle 1*-1=-1\)

Once you combine like-terms you end up with:

\(\displaystyle 2x^2+x-1\)

Example Question #160 : How To Use Foil In The Distributive Property

Simplify the following expression:

\(\displaystyle (3x+3)(-3x-3)\)

Possible Answers:

\(\displaystyle 9x^2+9\)

\(\displaystyle -9x^2-18x-9\)

\(\displaystyle 9x^2-9\)

\(\displaystyle 0\)

\(\displaystyle -9x^2-9x\)

Correct answer:

\(\displaystyle -9x^2-18x-9\)

Explanation:

To do this you must distribute using the FOIL method.

\(\displaystyle (3x+3)(-3x-3)\)

\(\displaystyle -9x^2-9x-9x-9\)

Simplify:

\(\displaystyle -9x^2-18x-9\)

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