Question

Do it fast given
x(x+y+z)=a-yz
y(x+y+z)=b-xz
z(x+y+z)=c-xy
Solve it
You will get 50 points

Answer 1

xy/(x+y) is the same as 1/(1/x+1/y)

so we can rewrite xy/(x+y) = a as 1/x+1/y = xy/(x+y) is the same as

1/(1/x+1/y) so we can rewrite xy/(x+y) = a as 1/x+1/y = 1/a (1)

also rewrite xz/(x+z) = b as 1/x+1/z = 1/b (2)

add (1) and (2)

==> 2/x+1/y+1/z = 1/a+1/b

but we also know that 1/z+1/y = 1/c

so 2/x+1/c = 1/a+1/b

so 2/x = 1/a+1/b-1/c = (bc+ac-ab)/abc

so x = 2abc / (bc+ac-ab) QED

Answer 2

I know and I will help u

x(x+y+z)= x^2