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Factorize the following

(i)4x^{2}+20x+25

(ii)9y^{2}-66yz+121z^{2}

(iii)\left ( 2x+\frac{1}{3} \right )^{2}-\left ( x-\frac{1}{2} \right )^{2}

Answers (1)

(i)\left ( 2x+5 \right )\left ( 2x+5 \right ) 

Solution

Given, 4x^{2}+20x+25

We can write the given expression as:

 (2x)^{2}+(5)^{2}+2(2x)(5) \; \; \; \; \cdots (i)                                   

Now, we know that

(a+b)^{2}=a^{2}+b^{2}+2ab  

Comparing equation (i) with the above identity, we have:

a = 2x, b = 5

So, 

\\(2x)^{2}+(5)^{2}+2(2x)(5) =(2x+5)^{2}\\ =(2x+5)(2x+5)  

(ii)\left ( 3y-11z \right )\left ( 3y-11z \right ) 

Solution

Given, 9y^{2}-66yz+121z^{2}

We can write the given expression as:

(3y)^{2}+(11z)^{2}-2(3y)(11z) \; \; \; \; \cdots (i)                                   

Now, we know that

(a-b)^{2}=a^{2}+b^{2}-2ab  

Comparing equation (i) with the above identity, we have:

a = 3y, b = 11z

So, 

\\=(3y)^{2}+(11z)^{2}-2(3y)(11z)=(3y-11z)^{2}\\ =(3y-11z)(3y-11z) 

(iii)\left ( x+\frac{5}{6} \right )\left ( 3x-\frac{1}{6} \right ) 

Solution

Given, \left ( 2x+\frac{1}{3} \right )^{2}-\left ( x-\frac{1}{2} \right )^{2}

Now, we know that

a^{2}-b^{2}=(a-b)(a+b)             

So, 

\\ \left ( 2x+\frac{1}{3} \right )^{2}-\left ( x-\frac{1}{2} \right )^{2}=\left ( 2x+\frac{1}{3}- \left ( x-\frac{1}{2} \right )\right ).\left ( 2x+\frac{1}{3}+ \left ( x-\frac{1}{2} \right )\right )\\ =\left ( 2x+\frac{1}{3}- x+\frac{1}{2} \right ).\left ( 3x+\frac{2-3}{6} \right )\\ =\left ( x+\frac{2+3}{6} \right )\left ( 3x-\frac{1}{6} \right )\\ =\left ( x+\frac{5}{6} \right )\left ( 3x-\frac{1}{6} \right )

Hence the factorized form is: \left ( x+\frac{5}{6} \right )\left ( 3x-\frac{1}{6} \right ).

Posted by

infoexpert24

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