How do you solve 9 - x = 10 using algebraic operations?

Me what is the value of x? showing work would be appreciated - ! : )

Select all of the quadrants that the parabola whose equation is y=√x-4 (principal square root) occupies. i ii iii iv

Hurry if the population of of an ant hill doubles every 10 days and there are currently 100 ants living in the ant hill what will the ant population be in 20 days