Q82 of 134 Page 4


Find two consecutive odd natural numbers, the sum of whose squares is 202.


Let the two consecutive odd natural numbers be x and x + 2.
x 2 + (x + 2) 2 = 202
x 2 + x 2 + 4x + 4 = 202
2x 2 + 4x + 198 = 0
x 2 + 2x + 99 = 0
x 2 + 11x – 9x + 99 = 0
x(x + 11) – 9(x + 11) = 0
(x – 9)(x + 11) = 0
x – 9 = 0 or x + 11 = 0
x = 9 or x = -11
Therefore the two consecutive odd natural numbers are 9 and 11.

Checking:
9 2 + 11 2 = 81 + 121 = 202.

More from this chapter

All 134 →