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NCERT Class XI Mathematics - Binomial Theorem - Solutions

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Question : 3 of 36
Marks: +1, -0
(2x3)6(2x-3)^6
Solution:  
We have, (2x3)6(2x-3)^6 = [2x+(3)]6[2x+(-3)]^6
= 6C0(2x)6+6C1(2x)5(3)\,{}^{6}C_{0}(2x)^6+\,{}^{6}C_{1}(2x)^5(-3) + 6C2(2x)4(3)2\,{}^{6}C_{2} (2x)^4(-3)^2 + 6C3(2x)3(3)2\,{}^{6}C_{3}(2x)^3(-3)^2 + 6C4(2x)2(3)4\,{}^{6}C_{4}(2x)^2(-3)^4 + 6C5(2x)(3)5\,{}^{6}C_{5}(2x)(-3)^5 + 6C6(3)6\,{}^{6}C_{6} (-3)^6
= 1(64x6)+6(32x5)(3)1(64x^6)+6(32x^5)(-3) + 15(16x4)(9)+20(8x3)(27)15(16x^4)(9)+20(8x^3)(-27) + 15(4x2)(81)15(4x^2)(81) + 6(2x)(243)+1(729)6(2x)(-243)+1(729)
= 64x6576x5+2160x44320x364x^6-576x^5+2160x^4-4320x^3 + 4860x3+4860x24860x^3+4860x^2 - 2916x + 729
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