again.. im lost with finding slope intercept and standard form of this equation as well.

x intercept =2, y intercept= -4

aren't you just given the two points

(2,0) and (0,-4) ?
from that you can find the slope
= (-4-0)/(0-2) = 2

so in y= mx+b you now know m and b
to give you
y = 2x - 4

which can be rearranged to
2x - y = 4

there is another very easy way to find the equation of a straight line if you know the x-intercept 'a' and the y-intercept 'b'

the equation is
x/a + y/b = 1

so here x/2 + y/-4 = 1

multiply by 4 to get
2x - y = 4 (just as above)