Question

Factorise 4x^2+y^2+25z^2 + 4xy-10yz-20zx find the value when x=-1 ,y=2 and z=-3

Answer 1

$4 {x}^{2} + {y}^{2} + 25 {z}^{2} + 4xy - 10yz - 20zx \\ {(2x)}^{2} + {y}^{2} + {(5z)}^{2} + 2(2x)y + 2(y)( - 5z) + 2(2x)( - 5z) \\ ={ (2x + y - 5z) }^{2} \\ = {(2 \times - 1 + 2 - 5 \times - 3)}^{2} \\ = {( - 2 + 2 + 15)}^{2} \\ = {15}^{2} \\ = 225$

Answer 2

This is your answer i think so that values you gibe in this,are wrong please,recheck