The sum of two irrational number is always

In δabc, if the length of side b is 3 centimeters and the measures of ∠b and ∠c are 45° and 60°, respectively, what is the length of side c to two decimal places?

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

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