Under a sign of absolute value can stay positive or negative number. If it is a positive number then the its absolute value is a number.
1) p-1=4 p=4+1 p=5
If it is a negative number then the its absolute value is a opposite of a number. 2) -(p-1)=4 -p+1=4 -p=4-1 -p=3 p=-3 So, this equation has 2 roots p=5, and p=-3.