Question 912341
Better is you not use rendering tags for the description.


"find two consecutive numbers whose product is 72"


You should remember the basic multiplication fact, {{{9*8=8*9=72}}}.  Knowing this, you can do the algebra exercise and know in advance if your result is wrong or correct.


Two number, x and x+1.  You assume x is an integer, probably a whole number.
{{{x(x+1)=72}}}
{{{x^2+x=72}}}
{{{x^2+x-72=0}}}
You then hope to be able to factorize the trinomial left member, and knowing your basic multiplication facts, you find that 8 and 9 are good choices to start with so....
(x-8)(x+9)=0 seems to work.


Your description uses, "consecutive numbers", which could possibly be INTEGERS, meaning POSITIVE AND NEGATIVE WHOLE NUMBERS.  


Looking just first for solutions to x, 
x=8  OR  x=-9.


Now, you want to evaluate the consecutive number.
For x=8, the next number is 9.
For x=-9, the next number is -8.


You then really have TWO possible answers.
The numbers you want are 8 and 9
OR
The numbers you want can be -9 and -8.



Those are your TWO SOLUTIONS.