Question 149681
1. {{{abs(v)=sqrt((-2)^2+(-4)^2)=sqrt(4+16)=sqrt(20)=2*sqrt(5)}}}
2. {{{v[1]=v/abs(v)}}}
{{{v[1]=4j/4}}}
{{{v[1]=j}}}
3. (5,-3) Starting at the origin, that 5 right, 3 down. 
4th Quadrant.
{{{drawing( 300, 300, -6, 6, -6, 6,grid( 1 ),green(line(5,-3,4.7,-3)),green(line(5,-3,5,-2.7)),green(line( 0, 0, 5, -3)))}}}
4.{{{v = -i + j}}}
{{{  -3(v)=(-3)(-i)+(-3)j}}}
{{{  -3(v)=3i-3j}}}