Alright, the final 2.
5.
\(x+y+z=6,\ x(y+z)=5, \ \text{and} \ y(x+z)=8\)
From the first equation, we can get:
\(y+z=6-x \ \text{and}\ x+z=6-y\)
We can plug this into equations 2 and 3.
\(x(6-x)=5 \\ 6x-x^2-5=0 \\ x^2-6x+5=0 \\ (x-1)(x-5)=0 \\ x_1=1 \ \text{and} \ x_2=5\)
and
\(y(6-y)=8 \\ 6y-y^2=8 \\ y^2-6y+8=0 \\ (y-2)(y-4)=0 \\ y_1=2 \ \text{and} \ y_2=4\)
We plug our x values and y values to find z.
Our four solution sets, (x, y, z) are:
(1, 2, 3) ; (1, 4, 1) ; (5, 2, -1) ; (5, 4, -3)