Question

Show that x=-2 is a solution of x2-2x+8=0

Answer 1

put x= -2
$= ( - 2) {}^{2} - 2 \times - 2 + 8 \\ = 4 + 4 + 8 \\ = 16$

Answer 2

if x=-2 is solution of this expression then on substituting this value R= 0
R=(-2)^2-2(-2)+8
=4+4+8
=16
As R is not equal to 0 it is not the solution of given expression