Question

What is the smallest of 3 consecutive positive integers if the product of the smallest and largest is 21 more than 9 times the middle number?

x(x+2)=21+9(x+1)
I'm not sure if this is a good equation to solve it..?

Answer 1

They are POSITIVE, odd numbers are OUT
so they differ by TWO

n-2 , n , n+2

(n-2)(n+2) = 21 + 9 n

Answer 2

n^2 - 4 = 21 + 9 n

n^2 - 9 n -21 = 0

(n-7)(n+3) = 0

n = 7
so the smallest is 5