If $x=1,\ y=2$ and $z=5$, find the value of $3x-2y+4z$.

Given: If $x=1,\ y=2$ and $z=5$.

To do: To find the value of $3x-2y+4z$.

Solution:

$3x-2y+4z$

$=3(1)-2(2)+4(5)$

$=3-4+20$

$=19$

Thus,  the value of $3x-2y+4z=19$.