Solve the equations
m2 + n2 = 29
m + n = 7
- (2, 3) and ( 3, 5)
-
(2, 5) and (5, 2)
- (5, 2) and ( 5, 3)
- (5, 3) and (3, 5)
The correct answer is: B
Explanation
m2 + n2 = 29 .......(1)m + n = 7 ............(2)
From (2),
m = 7 - n
but m2 + n2 = 29, substituting;
(7-n)2 + n2 = 29
49 - 14n + n2 + n2 = 29
=> 2n2 -14n + 20 = 0
Thus n2 -7n + 10 = 0
Factorizing;
(n-5)(n-2) = 0
n - 5 = 0, => n = 5
n - 2 = 0, => n = 2.
When n = 5,
m + n = 7, => m = 2,
When n = 2,
m + n = 7, => m = 5.
Thus (m,n) = (5,2) and (2,5)
There is an explanation video available .