Question

What is the solution to 2x2+x+2 = 0?

Answer 1

Explanation:

Plug this into the quadratic formula. It's the easiest and surest way to solve a quadratic.

a = 2

b = 1

c = 2

Filling in the quadratic formula:

`x=(-1+/-√(1^2-4(2)(2)) )/(2*2)`

which simplifies to

`x=(-1+/-√(-15) )/(4)`

You can't have a negative under the square root sign (or ay even index radical, for that matter), so we will rewrite it as

`x=(-1+/-√((-1)(15)) )/(4)`

and since i-squared is equal to -1:

`x=(-1+/-√(15i^2) )/(4)`

The only perfect square we can pull out of that square root is the i from the i-squared, so when we do that we get:

`x=-(1+/-√(15)i )/(4)`

or you could put the i out front; it doesn't change the answer at all. The third choice down is the one you want.