Math Word Problem 15

Question

The product of two consecutive integers is nine less than nine times there sum. find the integers

Answer 1

xy = 9(x+y) -9

xy = 9x +9y -9

n(n+1) = 9(n) + 9(n+1) -9

n^2 +n = 18n

n^2 -17n = 0

n(n-17)

n= 0 or 17

two consecutive integers are 0 and 1, or 17 and 18

0(1) = 9(0+1)-9

or

17(18) = 9(17+18)-9

306 = 315-9