Who know answer only they will give answers. And who don't know and still giving answer. Then I report his or her answer. THANK YOU. Question no. 17, 18, 19. with solutions.
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17 b
This is because
(x+y)^3 -( x^3 +y3) = (x+y)^3 -(x+y)(x^2 + y^2 -xy)
{identity : - a^3 +b^3 = (a+b)(a^2 +b^2 -ab)
18 .. a) option
Because x is already not having any coefficient ( that is 1) so after cubing it is x^3 with 1 as coefficient
From the given expression,
We get
x^2 +y^2 = -xy
Therefore x^3 - y ^3 = ( x - y)( x^2 + y ^2 + xy) = 0 since x^2 + y^2 = -xy
Therefore answer is option c )
Hope u understood
If any confusion u can ask me
Thank u★★★
#ckc
This is because
(x+y)^3 -( x^3 +y3) = (x+y)^3 -(x+y)(x^2 + y^2 -xy)
{identity : - a^3 +b^3 = (a+b)(a^2 +b^2 -ab)
18 .. a) option
Because x is already not having any coefficient ( that is 1) so after cubing it is x^3 with 1 as coefficient
From the given expression,
We get
x^2 +y^2 = -xy
Therefore x^3 - y ^3 = ( x - y)( x^2 + y ^2 + xy) = 0 since x^2 + y^2 = -xy
Therefore answer is option c )
Hope u understood
If any confusion u can ask me
Thank u★★★
#ckc
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