Question

2x^2=-8x+10

I got
x=-2-1i
x=-2+1i
But every time I plug the numbers back into the equation I am not getting the sides to equal. Not sure how to use the imaginary i.

Answer 1

you don't have to use the Quadratic formula for this, it is factorable upon rewriting, 2x^2+8x-10=0 and factoring out a 2, 2(x^2+4x-5)=0

You should get, 2(x+5)(x-1) making x = -5 and 1.

Answer 2

My chemistry professor wants us to use the quadratic formula

Answer 3

First you should factor out the 2 to leave X^2 + 4x -5 = 0. You should not be getting an i. Getting an i means you are a negative under the square root.
Your problem is that you're not doing the part under the square root sign correctly.
sqrt(b^2-4*a*c)
sqrt(16-4*1*-5)
sqrt(16+20)
sqrt(36)
+/- 6
so you have
(-4 +-6)/2 = -5,1
and 5,1 will satisfy the equation.

Answer 4

okay thank you