What is the simplest form of square root a^7

Answer in the photo

Find the volume of the described solid.the solid lies between planes perpendicular to the x-axis at x = 0 and x=7. the cross sectionsperpendicular to the x-axis between these planes are squares whose bases run from the parabolay=-31x to the parabola y = 30/x.a) 441b) 147c) 864d) 882

The? half-life of a radioactive substance is 20 years. if you start with some amount of this? substance, what fraction will remain in 120 ? years

Using inductive reasoning, what is the next two numbers in this set? 1,-7,13,-19 i got the numbers 14,-26 is that right?