Answer:
p =-2
Explanation:
The slope is given by
m = (y2-y1)/(x2-x1)
We have points (4p,-7) and (1,8) and the slope is 5/3
Substituting these in
5/3 = (8--7)/ (1-4p)
Simplifying
5/3 = (8+7)/ (1-4p)
Multiply by (1-4p) on both sides
5/3 (1-4p) = (15)/ (1-4p) * (1-4p)
5/3 (1-4p) = (15)
Multiply by 3 on both sides
5/3 *3(1-4p) = 3*(15)
5(1-4p) = 45
Distribute
5 - 20p = 45
Subtract 5 from each side
5-5-20p = 45-5
-20p = 40
Divide by -20
-20p/-20 = 40/-20
p =-2