SOLUTION: Solve. Try factoring first. If factoring is not possible or is difficult, use the quadratic formula. 2x^2 + 8 = -1

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Solve. Try factoring first. If factoring is not possible or is difficult, use the quadratic formula. 2x^2 + 8 = -1      Log On


   

Question 173804This question is from textbook Introductory Algebra
: Solve. Try factoring first. If factoring is not possible or is difficult, use the quadratic formula.
2x^2 + 8 = -1 This question is from textbook Introductory Algebra

Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
2x%5E2+%2B+8+=+-1
2x%5E2+%2B+9+=+0
no easy factoring there
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 2x%5E2%2B0x%2B9+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%280%29%5E2-4%2A2%2A9=-72.

The discriminant -72 is less than zero. That means that there are no solutions among real numbers.

If you are a student of advanced school algebra and are aware about imaginary numbers, read on.


In the field of imaginary numbers, the square root of -72 is + or - sqrt%28+72%29+=+8.48528137423857.

The solution is

Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+2%2Ax%5E2%2B0%2Ax%2B9+%29