Find two consecutive positive integers, sum of whose squares is 365.
Answers
Let us say, the two consecutive positive integers be x and x + 1.
Therefore, as per the given statement,
x2 + (x + 1)2 = 365
⇒ x2 + x2 + 1 + 2x = 365
⇒ 2x2 + 2x – 364 = 0
⇒ x2 + x – 182 = 0
⇒ x2 + 14x – 13x – 182 = 0
⇒ x(x + 14) -13(x + 14) = 0
⇒ (x + 14)(x – 13) = 0
Thus, either, x + 14 = 0 or x – 13 = 0,
⇒ x = – 14 or x = 13
since, the integers are positive, so x can be 13, only.
So, x + 1 = 13 + 1 = 14
Therefore, the two consecutive positive integers will be 13 and 14.
Step-by-step explanation:
Let the numbers be x and x+1
Square of consecutive number: x² and (x+1)²
Sum of square: x² + (x+1)² = 365
Lets solve
x²+x²+2x+1 = 365
2x²+2x-364=0
x²+x-182=0
(Dividing by 2)
Factorise,
x²+14x-13x-182=0
x(x+14)-13(x+14)=0
(x+14)(x-13)=0
∴x=-14 and+13
Since numbers are positive integers,x=13
So, required consecutive numbers are 13 and 14.