Question

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

Answer 1

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 ?

Answer 2

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