A) only (i) and (iii)
B) only (ii) and (iii)
C) only (i) and (ii)
D) (i), (ii) and (iii)
Correct Answer: C
Solution :
\[\left[ {{(5x-3y)}^{2}}+{{(5x+3y)}^{2}} \right]\] Put \[x=-1,y=\frac{1}{5},\]we get \[{{\left[ 5(-1)-3\left( \frac{1}{5} \right) \right]}^{2}}-{{\left[ 5(-1)+3\left( \frac{1}{5} \right) \right]}^{2}}\] \[={{\left[ -5-\frac{3}{5} \right]}^{2}}-{{\left[ -5+\frac{3}{5} \right]}^{2}}\] \[=\left[ -5-\frac{3}{5}+5-\frac{3}{5} \right]\left[ -5-\frac{3}{5}-5+\frac{3}{5} \right]\] \[=\left( -\frac{6}{5} \right)(-10)=12\] (iii) \[\left( x+4 \right)\left( x-4 \right)\left( {{x}^{2}}+16 \right)\] \[=\left( {{x}^{2}}-16 \right)\left( {{x}^{2}}+16 \right)=\left( {{x}^{4}}-256 \right)\]You need to login to perform this action.
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