Question

If h and j are positive, (h+j)2 = 73 and h2 +j2 = 51, what is hj?

Answer 1

`hj = 11`

Explanation:

• 
  `(h+j)^2=73,\:\: and\:\: h^2+j^2 =51` (Given)

• 
  `(h+j)^2 = h^2+j^2 +2hj`

• 
  `\implies 73= 51 +2hj`

• 
  `\implies 73- 51 =2hj`

• 
  `\implies 22 =2hj`

• 
  `\implies hj = (22)/(2)`

• 
  `\implies hj = 11`