Factorise the following using appropriate identities:
(i) 9x 2 + 6xy + y 2
(ii) 4y 2 – 4y + 1
(iii) x 2 – \(\frac{y^2 }{ 100}\)
(i) 9x2 + 6xy + y2 = (3x)2 + 2(3x)(y)+(y)2
= (3x + y)(3x + y) [x2 + 2xy + y2 = (x + y)2]
(ii) 4y2 - 4y + 1 = (2y)2 - 2(2y)91) + (1)2
= (2y - 1)(2y - 1) [x2 - 2xy + y2 = (x - y)2]
(iii) x2 -\(\frac{y^2 }{ 100}\) = x2 - (\(\frac{y }{ 10}\))2
= (x + \(\frac{y }{ 10}\)) (x -\(\frac{y }{ 10}\)) [x2 - y2 = (x + y) (x - y)]
Factorise each of the following:
(i) 8a 3 + b 3 + 12a 2b + 6ab2
(ii) 8a 3 – b 3 – 12a 2b + 6ab2
(iii) 27 – 125a 3 – 135a + 225a 2
(iv) 64a 3 – 27b 3 – 144a 2b + 108ab2
(v) 27p 3 – \(\frac{1}{ 216}\) – \(\frac{9 }{ 2}\) p2 + \(\frac{1 }{4}\) p
Expand each of the following, using suitable identities:
(i) (x + 2y + 4z) 2 (ii) (2x – y + z) 2 (iii) (–2x + 3y + 2z) 2
(iv) (3a – 7b – c) 2 (v) (–2x + 5y – 3z) 2 (vi) [ \(\frac{1 }{ 4}\) a - \(\frac{1 }{ 2}\) b + 1]2
Use these adverbs to fill in the blanks in the sentences below.
awfully sorrowfully completely loftily carefully differently quickly nonchalantly
(i) The report must be read ________ so that performance can be improved.
(ii) At the interview, Sameer answered our questions _________, shrugging his shoulders.
(iii) We all behave _________ when we are tired or hungry.
(iv) The teacher shook her head ________ when Ravi lied to her.
(v) I ________ forgot about it.
(vi) When I complimented Revathi on her success, she just smiled ________ and turned away.
(vii) The President of the Company is ________ busy and will not be able to meet you.
(viii) I finished my work ________ so that I could go out to play