How do you find the quotient of $\dfrac{{{x^3} + 27}}{{x + 3}}$?
Answer
601.2k+ views
Hint: Here, we will use the identity of the sum of cubes of two terms and then find the common factor from the numerator and the denominator and then the resultant term is quotient.
Complete step by step solution:
Take the given expression: $\dfrac{{{x^3} + 27}}{{x + 3}}$
Use the identity of the sum of the cubes as ${a^3} + {b^3} = (a + b)({a^2} - ab + {b^2})$in the above equation.
Here, $a = x$ and $b = 3$
\[{(x)^3} + {(3)^3} = (x + 3)\left( {{{(x)}^2} - (x)(3) + {{(3)}^2}} \right)\]
Simplify the above expression –
\[{(x)^3} + {(3)^3} = (x + 3)\left( {{x^2} - 3x + 9} \right)\]
Place the above value in the given expression –
\[\dfrac{{{x^3} + 27}}{{x + 3}} = \dfrac{{(x + 3)\left( {{x^2} - 3x + 9} \right)}}{{(x + 3)}}\]
Common factors from the numerator and the denominator cancels each other. Therefore, remove $(x + 3)$from the numerator and the denominator.
Using the Division Algorithm which states that –
Dividend $ = $Divisor $ \times $Quotient $ + $Remainder
So, it applies that Quotient is \[\left( {{x^2} - 3x + 9} \right)\]
So, the correct answer is “ \[\left( {{x^2} - 3x + 9} \right)\] ”.
Note: Know the concepts of squares and cubes. Square is the number multiplied itself and cube it the number multiplied thrice. Square is the product of same number twice such as ${n^2} = n \times n$ for Example square of $2$ is ${2^2} = 2 \times 2$ simplified form of squared number is ${2^2} = 2 \times 2 = 4$ and square-root is denoted by $\sqrt {{n^2}} = \sqrt {n \times n} $ For Example: $\sqrt {{2^2}} = \sqrt 4 = 2$ Similarly cube is the product of same number three times such as ${n^3} = n \times n \times n$ for Example cube of $2$ is ${2^3} = 2 \times 2 \times 2$ simplified form of cubed number is ${2^3} = 2 \times 2 \times 2 = 8$. and cube-root is denoted by $\sqrt[3] {{{n^3}}} = \sqrt {n \times n \times n} = n$ For Example: $\sqrt[3] {8} = \sqrt[3] {{{2^3}}} = 2$ Do not be confused in square and square-root similarly cubes and cube-root, know the concepts properly and apply accordingly.
Complete step by step solution:
Take the given expression: $\dfrac{{{x^3} + 27}}{{x + 3}}$
Use the identity of the sum of the cubes as ${a^3} + {b^3} = (a + b)({a^2} - ab + {b^2})$in the above equation.
Here, $a = x$ and $b = 3$
\[{(x)^3} + {(3)^3} = (x + 3)\left( {{{(x)}^2} - (x)(3) + {{(3)}^2}} \right)\]
Simplify the above expression –
\[{(x)^3} + {(3)^3} = (x + 3)\left( {{x^2} - 3x + 9} \right)\]
Place the above value in the given expression –
\[\dfrac{{{x^3} + 27}}{{x + 3}} = \dfrac{{(x + 3)\left( {{x^2} - 3x + 9} \right)}}{{(x + 3)}}\]
Common factors from the numerator and the denominator cancels each other. Therefore, remove $(x + 3)$from the numerator and the denominator.
Using the Division Algorithm which states that –
Dividend $ = $Divisor $ \times $Quotient $ + $Remainder
So, it applies that Quotient is \[\left( {{x^2} - 3x + 9} \right)\]
So, the correct answer is “ \[\left( {{x^2} - 3x + 9} \right)\] ”.
Note: Know the concepts of squares and cubes. Square is the number multiplied itself and cube it the number multiplied thrice. Square is the product of same number twice such as ${n^2} = n \times n$ for Example square of $2$ is ${2^2} = 2 \times 2$ simplified form of squared number is ${2^2} = 2 \times 2 = 4$ and square-root is denoted by $\sqrt {{n^2}} = \sqrt {n \times n} $ For Example: $\sqrt {{2^2}} = \sqrt 4 = 2$ Similarly cube is the product of same number three times such as ${n^3} = n \times n \times n$ for Example cube of $2$ is ${2^3} = 2 \times 2 \times 2$ simplified form of cubed number is ${2^3} = 2 \times 2 \times 2 = 8$. and cube-root is denoted by $\sqrt[3] {{{n^3}}} = \sqrt {n \times n \times n} = n$ For Example: $\sqrt[3] {8} = \sqrt[3] {{{2^3}}} = 2$ Do not be confused in square and square-root similarly cubes and cube-root, know the concepts properly and apply accordingly.
Recently Updated Pages
Find the greatest six digit number that is exactly class 8 maths CBSE

What is the time difference between India and Cana class 8 social science CBSE

Compare LPG and wood as fuels class 8 chemistry CBSE

In Indian rupees 1 trillion is equal to how many c class 8 maths CBSE

30 opposite words in English from a to z class 8 english CBSE

How many cubic feet equals to 1 unit sand class 8 maths CBSE

Trending doubts
What is BLO What is the full form of BLO class 8 social science CBSE

Citizens of India can vote at the age of A 18 years class 8 social science CBSE

Full form of STD, ISD and PCO

One cusec is equal to how many liters class 8 maths CBSE

What are the methods of reducing friction. Explain

What is the difference between rai and mustard see class 8 biology CBSE


