Question 825996
The product of two consecutive numbers is 72. Use a quadratic equation to find the two sets of numbers.
So, (x - 8)(x-9) = 0 ******* You started by knowing the answer.
x^2 + -17 + 72 = 0
ax^2 + bx + c, where a = 1, b = -17 and c = 72.
"Plug" into x = b+-sqrt4ac/2a

I found online that: 
-17 + sqrt(1) 
-17 + 1 = -16/2 = -8 
-17 - 1 = -18/2 = -9 

Aren't you meant to plug in all the numbers in the equation? Why am I getting decimal numbers?  What decimal numbers?