Does anyone know -sqrt (-9) ?

Thank you!

Can some one me, i’ve been asking for so long

Which equation represents a direct linear variationa. y=x2b. y=2/5xc. y=1/xd. y=x+3

An unknown number x is at most 10. which graph best represents all the values of x? number line graph with closed circle on 10 and shading to the right. number line graph with open circle on 10 and shading to the right. number line graph with open circle on 10 and shading to the left. number line graph with closed circle on 10 and shading to the left.