Question

Find the value of x+y+z if x^2+y^2+z^2=18 and xy+yz+xz=9

Answer 1

Answer:

${x}^{2} + {y}^{2} + {z}^{2} = 18 \\ = (x + y + z) ^{2} = 18 \\ x + y + z = \sqrt{18}$