Find all pairs (x,y) of real numbers such that x + y = 10 and x^2 + y^2 = 56 - 3xy. For example, to enter the solutions (2,4) and (-3,9), you would enter "(2,4),(-3,9)" (without the quotation marks).
x = 5 - sqrt(69), y = 5 + sqrt(69)
x = 5 + sqrt(69), y = 5 - sqrt(69)
