Question

if x+y+z=12and x2+y2+,z2=64then xy +yz+zx​

Answer 1

Answer:

Step-by-step explanation:

Squaring both sides

(x+y+z)

2

=x

2

+y

2

+z

2

+2(xy+yz+zx)

we can substitute given values

(x+y+z)

2

=18+(2×9)

(x+y+z)

2

=36

(x+y+z)=6

Answer 2

Answer:

(x+y+z)2=x2+y2+z2+2xy+2yz+2zx

122=64+2(xy+yz+zx)

144-64=2(xy+yz+zx)

80=2(xy+yz+zx)

xy+yz+zx=40