Question 729382
Y=mX+b where m=the slope & b=the y intercept.
y=1/2x-4 this line has a slope=1/2. [red lone]
2x+4y=9
4y=-2x+9
y=-2x/4+9/4
y=-x/2+2.25 this line has a slope=-1/2. green line.
PROOF: 
{{{ graph( 300, 200, -6, 10, -10, 10, x/2 -4, -x/2 +2.25) }}}