19q18

See https://www.beatthegmat.com/coordinate-s ... 12489.html for prior response.

However, here's another way to look at it:

From the question, we're basically asked whether:
r^2 + s^2 = u^2 + v^2

(1) Not sufficient. We have 4 variables from the question, but the statement only gives one other equation. We need 4 different equations with the variables above to solve the question.

(2) Not sufficient. Just by looking at the given equations, we will end up with 2 variables (r & s). We still cannot solve the question.

Combined: Sufficient. The equation (with substitution) from Stem #2 and Stem #1 are not the same, and we have 2 different equations for 2 different variables.