What two positive consecutive integers have a product of 72?

1 answer

a = first mumber

b = second number

b = a + 1

a ∙ b = 72

a ∙ ( a + 1 ) = 72

a² + a = 72

a² + a - 72 = 0

The solutions are:

a = - 9 and 8

For a = - 9

b = a + 1 = - 9 + 1 = - 8

For a = 8

b = a + 1 = 8 + 1 = 9

The solutions are:

a = - 9 , b = - 8

and

a = 8 , b = 9

( - 9 ) ∙ ( - 8 ) = 72

8 ∙ 9 = 72