Help me pretty please

The sum of two numbers is 86, and their difference is 20. find the two numbers

The square pyramid has a volume of 441 cubic inches. what is the value of x? 1/7x is the height x is the base

1. writing an equation for an exponential function by 2. a piece of paper that is 0.6 millimeter thick is folded. write an equation for the thickness t of the paper in millimeters as a function of the number n of folds. the equation is t(n)= 3. enter an equation for the function that includes the points. (-2, 2/5) and (-1,2)