If there are two values of ' a ' which makes determinant = | array ccc 1 & -2 & 5 2 & a & -1 0 & 4 & 2 a array |=86 Then, the sum of these number is

Step-by-step solution

Given, = | array ccc 1 & -2 & 5 2 & a & -1 0 & 4 & 2 a array |=86 aligned & | array ccc 1 & -2 & 5 2 & a & -1 0 & 4 & 2 a array |=86 & 1 [2 a^2+4 ]+2[4 a+0]+5[8-0]=86 & 2 a^2+4+8 a+40=86 & 2 a^2+8 a-42=0 a^2+4 a-21=0 & a^2+7 a-3 a-21=0 (a+7)(a-3)=0 & Required sum =-7+3=-4 aligned