The equation of a line is written as y=mx+b where m is the slope and b is the y-intercept.
To find the slope: m=y2 - y1 / x2 -x1
#28. m = (-12) - 0/ 4-0
m = -12/4
m = -3
so your slope is -3
the formula for figuring the line equation is:
y - y1 = m(x - x1)
y - 0 = -3(x - 0)
y = -3x +0
so the answer to # 28 is y=-3x + 0
you should be able to figure out the others following this model