Question

Which of the following is a solution of x2 + 2x + 8?

4 + i times the square root of 7
−1 + i times the square root of 7
1 + i times the square root of 7
−4 + i times the square root of 7

Answer 1

use the quadratic formula \[\huge\rm \frac{ -b \pm \sqrt{b^2-4ac} }{ 2a }\]
\[\huge\rm Ax^2+Bx+C=0\]

where
a=leading coefficient
b=middle term
c=constant

Answer 2

and x^2 is same as 1x^2
there is invisible one