A) Pick any two points and use the formula (y2-y1)/(x2-x1) to find the slope:
(-8- -2)/(2-0) = -6/2 = 3
To find the y intercept, plug one of the points in the y=mx+b form and solve for b:
y=mx+b
4=3(-2)+b
4=-6+b
10=b
B) Using what we solved for, the equation would be y=3x+10