Algebra word problem

Question

oliver bought some sponges. The number of packages he bought was 3 less than the number of sponges per package. Oliver bought 70 sponges in all. How many sponges were in each package? 

Answer 1

number of  sponges per packets = x

 

number of packets = x-3

 

x(x-3) = 70

 

x²  -3x =70

 

x²   -3x -70 =0

 

(x-10)(x+7) =0

 

x=10 or x = -7

 

so

number of sponges per packets = x = 10