Question

What are the solutions of the equation 2x² = 8? Use a graph of the related function

what are the coordinates of the parabola??

Answer 1

Use geogebra to graph the equation after rearanging it like this \[y=2x ^{2}-8\]
http://www.geogebra.org/cms/

Solve the equation using the quadratic equation.

\[(-b \pm \sqrt{b ^{2}-4ac})/2a\]

In your equation. a=2 b=0 c=-8

Which becomes
\[-0/(2)(2)\pm (\sqrt{(0)^{2}-(4)(2)(-8)})/(2)(2)\]Which now becomes\[\pm(\sqrt{64})/4\]
So \[x=\pm2\]

check
\[y=(2)(-2)^{2}-8\]\[y=0\] So the solution checks for x=-2

Repeat for x=2