Question

solve x^2 + 7 = -3 using quadratic formula

Answer 1

\[ x^2+7 = -3\\
x^2+7+3=0\\
x^2+10 = 0\]
If you want, you can re-write this as:
\[ x^2+0x+10=0\], so then:
\[ x=\frac{-(0)\pm\sqrt{0^2-4(1)(10)}}{2(1)}\\
x=\frac{\pm\sqrt{-40}}{2}\\
x=\frac{\pm i\sqrt{40}}{2}=\frac{\pm2i\sqrt{10}}{2}=\pm i\sqrt{10}\]