PSAT Math : Trinomials

Study concepts, example questions & explanations for PSAT Math

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Example Questions

Example Question #1 : How To Factor A Trinomial

Factor the following expression completely:

\displaystyle x^4-8x^3+12x^2

Possible Answers:

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

\displaystyle x^2(x-3)(x-4)

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

\displaystyle x^2(x+3)(x+4)

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

Correct answer:

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

Explanation:

We must begin by factoring out \displaystyle x^2 from each term.

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

Next, we must find two numbers that sum to \displaystyle -8 and multiply to \displaystyle 12.

\displaystyle (-6)+(-2)=-8

\displaystyle -6*-2=12

Thus, our final answer is:

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

Example Question #2 : Trinomials

Factor the following trinomial:

\displaystyle x^2-x-12

Possible Answers:

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

\displaystyle (x-3)(x-4)

\displaystyle (x-1)(x-12)

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

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

Correct answer:

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

Explanation:

\displaystyle x^2-x-12

To trinomial is in \displaystyle ax+bx+c form

In order to factor, find two numbers whose procuct is \displaystyle c, in this case \displaystyle -12, and whose sum is \displaystyle b, in this case \displaystyle -1

Factors of \displaystyle -12:

\displaystyle -1, 12; 1, -12; -3,4; 3,-4;-2,6; 2,-6

Which of these pairs has a sum of \displaystyle -1?

\displaystyle 3 and \displaystyle -4

Therefore the factored form of \displaystyle x^2-x-12 is:

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

Example Question #1 : How To Factor A Trinomial

Factor the trinomial.

\displaystyle x^{2}-5x-14

Possible Answers:

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

\displaystyle (x-8)(x+3)

\displaystyle (x-3)(x-2)

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

Correct answer:

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

Explanation:

Our factors will need to have a product of \displaystyle (-14), and a sum of \displaystyle (-5), so our factors must be \displaystyle (-7) and \displaystyle 2.

Example Question #41 : Algebra

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

Possible Answers:

\displaystyle x^4+x^2y^2+y^2z^2+z^4

\displaystyle 2x^2y^2+z^4+y^4+2z^2y^2

\displaystyle x^4+y^4+z^4+2x^2y^2+2y^2z^2+2x^2z^2

\displaystyle x^4+y^4+z^4

\displaystyle x^2y^2+y^2z^2+x^2z^2

Correct answer:

\displaystyle x^4+y^4+z^4+2x^2y^2+2y^2z^2+2x^2z^2

Explanation:

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

Use the distributive property:

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

\displaystyle x^4+x^2y^2+x^2z^2 + x^2y^2+y^4+y^2z^2+x^2z^2+y^2z^2+z^4

Combine like terms:

\displaystyle x^4+y^4+z^4+2x^2y^2+2y^2z^2+2x^2z^2

Example Question #42 : Algebra

Find the product:

\displaystyle (x^2+7x+4)(x^2-3x-2)

Possible Answers:

\displaystyle x^4-10x^3+27x^2-14x-4

\displaystyle 2x^2-4x-2

\displaystyle x^4+4x^3-19x^2-26x-8

\displaystyle x^4-21x-8

\displaystyle 2x^2+4x+2

Correct answer:

\displaystyle x^4+4x^3-19x^2-26x-8

Explanation:

Find the product:

\displaystyle (x^2+7x+4)(x^2-3x-2)

Step 1: Use the Distributive Property

\displaystyle x^2(x^2-3x-2)+7x(x^2-3x-2)+4(x^2-3x-2)

\displaystyle x^4-3x^3-2x^2+7x^3-21x^2-14x+4x^2-12x-8

Step 2: Combine like terms

\displaystyle x^4+4x^3-19x^2-26x-8

Example Question #3 : Trinomials

Find the product:

\displaystyle (2x^2+3y+6)(7x^2+4y+1)

Possible Answers:

\displaystyle 21x^2y+12y^2+3y

\displaystyle 14x^2+29x^2y+44x^2+12y^2+27y+6

\displaystyle 14x^4+8x^2y+2x^2

\displaystyle 14x^2+8x^2y+12y^2+8

\displaystyle 42x^2+24y+6

Correct answer:

\displaystyle 14x^2+29x^2y+44x^2+12y^2+27y+6

Explanation:

Find the product:

\displaystyle (2x^2+3y+6)(7x^2+4y+1)

Use the distributive property:

\displaystyle 2x^2(7x^2+4y+1)+3y(7x^2+4y+1)+6(7x^2+4y+1)

\displaystyle 14x^4+8x^2y+2x^2+21x^2y+12y^2+3y+42x^2+24y+6

\displaystyle 14x^4+29x^2y+44x^2+12y^2+27y+6

Example Question #1 : Trinomials

Simplify:

\displaystyle (4x^2+6x+5)+(3x^3+10x+7)

Possible Answers:

\displaystyle 7x^2+16x+12

\displaystyle 7x^2+13x+15

\displaystyle 3x^3+4x^2+16x+12

 

\displaystyle 3x^3+4x^2+13x+15

Correct answer:

\displaystyle 3x^3+4x^2+16x+12

 

Explanation:

All operations are addition, so we can first remove the parentheses:

\displaystyle (4x^2+6x+5)+(3x^3+10x+7)

\displaystyle =4x^2+6x+5+3x^3+10x+7

Now rearrange the terms so that like terms are next to each other:

\displaystyle =3x^3+4x^2+(6x+10x)+(5+7)

Combine like terms:

\displaystyle =3x^3+4x^2+16x+12

 

Example Question #52 : Algebra

Add, expressing the result in simplest form:

\displaystyle \left ( 4x^{2}+ 9y^{2} \right ) + \left ( 2x^{2}- 4xy + 7y\right )

Possible Answers:

\displaystyle 6x^{2} + 16y^{2} - 4xy

\displaystyle 6x^{2} + 9y^{2} +3xy

\displaystyle 6x^{2} + 9y^{2} - 4xy + 7y

\displaystyle 6x^{2} + 16y^{3} - 4xy

\displaystyle 6x^{2} + 9y^{2} +3xy^{2}

Correct answer:

\displaystyle 6x^{2} + 9y^{2} - 4xy + 7y

Explanation:

\displaystyle \left ( 4x^{2}+ 9y^{2} \right ) + \left ( 2x^{2}- 4xy + 7y\right )

\displaystyle = 4x^{2}+ 2x^{2} + 9y^{2} - 4xy + 7y

\displaystyle = 6x^{2} + 9y^{2} - 4xy + 7y

Example Question #3 : Trinomials

Add, expressing the result in simplest form:

\displaystyle \left ( 4x^{2}+ 2xy + 7y^{2} \right ) + \left ( 2x^{2}+7y\right )

Possible Answers:

\displaystyle 6x^{2} + 2xy + 7y^{2} + 7y

\displaystyle 6x^{2} +9xy + 7y^{2}

\displaystyle 6x^{2} + 2xy + 14y^{2}

\displaystyle 4x^{2}+ 4xy + 7y^{2} +7y

\displaystyle 6x^{2} + 2xy + 14y^{3}

Correct answer:

\displaystyle 6x^{2} + 2xy + 7y^{2} + 7y

Explanation:

\displaystyle \left ( 4x^{2}+ 2xy + 7y^{2} \right ) + \left ( 2x^{2}+7y\right )

\displaystyle = 4x^{2}+ 2x^{2} + 2xy + 7y^{2} + 7y

\displaystyle = 6x^{2} + 2xy + 7y^{2} + 7y

Example Question #51 : Algebra

Add, expressing the result in simplest form:

\displaystyle \left ( \frac{1}{2}x^{2} + \frac{2}{3}x - \frac{1}{5}\right ) + \left ( \frac{1}{4}x^{2} - \frac{1}{4}x - \frac{1}{4}\right )

Possible Answers:

\displaystyle \frac{1}{6} x^{2} + \frac{11}{12}x - \frac{9}{20}

\displaystyle \frac{3}{4} x^{2} + \frac{5}{12}x + \frac{1}{20}

\displaystyle \frac{3}{4} x^{2} + \frac{5}{12}x - \frac{9}{20}

\displaystyle \frac{3}{4} x^{2} + \frac{11}{12}x - \frac{9}{20}

\displaystyle \frac{1}{6} x^{2} + \frac{5}{12}x + \frac{1}{20}

Correct answer:

\displaystyle \frac{3}{4} x^{2} + \frac{5}{12}x - \frac{9}{20}

Explanation:

\displaystyle \left ( \frac{1}{2}x^{2} + \frac{2}{3}x - \frac{1}{5}\right ) + \left ( \frac{1}{4}x^{2} - \frac{1}{4}x - \frac{1}{4}\right )

\displaystyle = \frac{1}{2}x^{2} + \frac{2}{3}x - \frac{1}{5} + \frac{1}{4}x^{2} - \frac{1}{4}x - \frac{1}{4}

\displaystyle = \frac{1}{2}x^{2} + \frac{1}{4}x^{2} + \frac{2}{3}x - \frac{1}{4}x- \frac{1}{5} - \frac{1}{4}

\displaystyle =\left ( \frac{1}{2} + \frac{1}{4} \right )x^{2} +\left ( \frac{2}{3} - \frac{1}{4} \right )x- \left (\frac{1}{5}+\frac{1}{4} \right )

\displaystyle =\left ( \frac{2}{4} + \frac{1}{4} \right )x^{2} +\left ( \frac{8}{12} - \frac{3}{12} \right )x- \left (\frac{4}{20}+\frac{5}{20} \right )

\displaystyle = \frac{3}{4} x^{2} + \frac{5}{12}x - \frac{9}{20}

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