Let √x=c
Let √y=d
The two given equations become:
c^2d+cd^2=14
c^3+d^3=22
If you cube (c+d), you will get an expression purely based on the two above equations:
(c+d)^3 = c^3+d^3+3c^2d+3cd^2
(c+d)^3 = 22 + 14*3
(c+d)^3 = 64
(c+d) = 4
Since the first equation can also be written as cd(c+d) = 14,
cd = 14/4 = 3.5
If you square (c+d) you get:
(c+d)^2 = c^2 + d^2 + 2cd
But c^2 = x and d^2 = y, and we know (c+d) and cd, so therefore we can rearrange to:
(x+y) = (c+d)^2 - 2cd = 16 - 7
(x+y) = 9