PSAT Math : Monomials

Study concepts, example questions & explanations for PSAT Math

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Example Questions

Example Question #71 : Algebra

If you have a rectangle with a width of \displaystyle 3n and a length of \displaystyle 7n-3y +2, what is the area of the rectangle?

Possible Answers:

\displaystyle 56n^{2}-27ny+18n

\displaystyle 21n-9y^{2}+6

\displaystyle 21ny-9ny+2ny

\displaystyle 21n^{2}-9ny+6n

\displaystyle 14ny^{3}

Correct answer:

\displaystyle 21n^{2}-9ny+6n

Explanation:

To find the area of a rectangle, multiply the length times the width.  Therefore, you must multiply \displaystyle 3n times \displaystyle 7n-3y +2.  To do that, you must multiply the monomial times each part of the trinomial, like so:

\displaystyle 7n(3n)-3y(3n) +2(3n)

\displaystyle 21n^2-9ny+6n

 

Example Question #722 : Psat Mathematics

Find the product:

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

Possible Answers:

\displaystyle 9x^5y^6+6x^3y^6+7

\displaystyle 1

\displaystyle 18x^6y^5z^4+6x^9y^5+42x^3y^5

\displaystyle 6x^3y^5z^4+6x^3y^5+7y^6

\displaystyle 18x^5y^5z^4 + 6x^6y^6+42x^3y^6

Correct answer:

\displaystyle 18x^5y^5z^4 + 6x^6y^6+42x^3y^6

Explanation:

Use the distributive property:

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

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

Simplify: don't forget to use the rules of multiplying exponents (add them)

\displaystyle 18x^5y^5z^4 + 6x^6y^6+42x^3y^6

Example Question #723 : Psat Mathematics

Find the product:

\displaystyle 4a^2(ab^2+a^2b+ac^3)

Possible Answers:

\displaystyle 4a^3b^2+4a^4b+4a^3b^3

\displaystyle 4ab^3+4a^2b^3+4ac

\displaystyle 4a^2b^3+4ab

\displaystyle 8a^2b^2+4a^4b

\displaystyle 4a^2b^2+4a^4b+4a^2b^3

Correct answer:

\displaystyle 4a^3b^2+4a^4b+4a^3b^3

Explanation:

Find the product:

\displaystyle 4a^2(ab^2+a^2b+ac^3)

Use the distributive property:

\displaystyle (4a^2\cdot ab^2)+(4a^2\cdot a^2b)+(4a^2\cdot ac^3)

When multiplying variables with exponents, add the exponents:

\displaystyle 4a^3b^2+4a^4b+4a^3c^3

Example Question #3 : Monomials

Find the product:

\displaystyle 5x^3(x^2+2x+4)

Possible Answers:

\displaystyle 5x^5+10x^4+20x^3

\displaystyle 5x^6+30x^3

\displaystyle 5x^2+2.5x^2+1.25x^3

\displaystyle 5x^6+10x^4+20x^3

\displaystyle 5x^3+x^2+2x+4

Correct answer:

\displaystyle 5x^5+10x^4+20x^3

Explanation:

Find the product:

\displaystyle 5x^3(x^2+2x+4)

Use the distributive property:

\displaystyle (5x^3 \cdot x^2)+(5x^3 \cdot 2x)+(5x^3 \cdot 4)

\displaystyle 5x^5+10x^4+20x^3

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