Question

In the equation, $x^6-12x^5+a{x}^4-b{x}^3+c{x}^2-dx+64=0$. Find a+b+c+d

• A. 362
• B. 662
• C. 562
• D. 652

Answer 1

The correct option is D 652

Ans. (d)

Since sum of roots is given to you as 12 and product as 64. the six roots are 2,2,2,2,2,2.

Sum of roots taken 2 at a time (a) = ${}^6{C}_2\times 4=60$

Sum of roots taken 3 at a time (b) = ${}^6{C}_3\times 8=160$

Sum of roots taken 4 at a time (c) = ${}^6{C}_4\times 16=240$

Sum of roots taken 5 at a time (d) = ${}^6{C}_5\times 32=192$

a+b+c+d=652