Choose the best option to fill in the blank a(n) - is the shortest path between points on a sphere

What is the solution of sqrt x+2-15=-3

Valentina is subtracting from . she finds the lcd to be 15y2. what is valentina's next step?

Use mathematical induction to prove the statement is true for all positive integers n, or show why it is false. 1^2 + 4^2 + 7^2 + + (3n - 2)^2 = [n(6n^2-3n-1)/2]