Answer:
p = 17 and -15
Step-by-step explanation:
If q is directly proportional to (p-1)², this can be written as;
q = k(p-1)²
If q = 20 when p = 3
20 = k(3-1)²
20 = 2²k
20 = 4k
k = 5
To get p wen q = 80
80 = 5(p-1)²
16 = (p-1)²
p-1 = ±√16
p-1 = 16 and p-1 = -16
p = 17 and p=-16+1
p = 17 and -15