AP EAMCET2009MathematicsDeterminants
If one of the roots of | array lll 3 & 5 & x 7 & x & 7 x & 5 & 3 array |=0 is -10 , then the other roots are
Options
- A3, 7
- B4, 7
- C3, 9
- D3, 4
Correct answer
A. 3, 7
Step-by-step solution
Given, | array lll 3 & 5 & x 7 & x & 7 x & 5 & 3 array |=0 array cc & 3(3 x-35)-5(21-7 x)+x (35-x^2 )=0 & 9 x-105-105+35 x+35 x-x^3=0 & x^3-79 x+210=0 & (x+10)(x-3)(x-7)=0 & x=-10,3,7 array