Find all real solution of the equation 10x2 14x16 0 7 squ

Find all real solution of the equation. 10x^2 - 14x-16 = 0 7 + squareroot 209/10, 7 - squareroot 209/10 14 + squareroot 111/20, 14 - squareroot 111/20 7 + squareroot 111/10, 7 - squareroot 111/10 14 + squareroot 444/20, 14 - squareroot 444/20 14 + squareroot 209/20, 14- squareroot 209/20

Solution

10x^2 -14x - 16 =0

Using the quadratic root solution:

x = ( 14 +/- sqrt( 14^2 + 4*10*16) )/20

= ( 14 +/- sqrt( 836) )/20

Since 836 = 4*209

= ( 14 +/- 2sqrt209 )/20

= ( 7 +/- sqrt209)/10

Option A