Question

Find the value of $$4{x}^{2}+{y}^{2}+25{z}^{2}+4xy-10yz-20zx$$ when $$x=4,y=3$$ and $$z=2$$

Answer 1

Correct option is A. 1

Given,

$$4x^2+y^2+25z^2+4xy-10yz-20zx$$

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

$$\Rightarrow 4(4)^2+(3)^2+25(2)^2+4(4)(3)-10(3)(2)-20(2)(4)$$

$$=64=9+100+48-60-160=1$$