Explanation

Solution :

If x= 2, y = 3, z = 4 then

$3x^2-4y^2+2z^2$

=$3(2)^2-4(3)^2+2(4)^2$

=$\left(3\times4\right)-\left(4\times9\right)+\left(2\times16\right)$

=$12-36+32$

=$44-36$

=$8$

∴ $3x^2-4y^2+2z^2=8$