For wich values of x does 2x^2+10x

2x^2 + 10x doesn't do anything, unless it's equal to something.

All you've got so far is a number. We can't even tell what it is

until we know what number 'x' is.

Is there another little part of the question that you didn't copy?

Factor out at 2 so 2 (x+5) (x+0)

Set them equal to 0 so

2=0 that's not a solution

X+5=0 so x=-5 that works

And the last one x=-0 well negative 0 doesn't exist so the only value that works is - 5