Question

Find the value of 4x^2 + y^2 + 25z^2 + 4xy − 10yz − 20zx when x = 4, y = 3 and z = 2.

Answer 1

solution

given that 4x²+y²+25z²+4xy-10yz

where x=4 ,y=3 , z=2

=4(4²)+3²+25(2)²+4*4*3-10(3*3*2)

=4(16)+9+25(4) +48-10(18)

=64+9+100+48-180

=41