JAMB - Mathematics (1990 - No. 15)
If a2 + b2 = 16 and 2ab = 7.Find all the possible values of (a - b)
3, -3
2, -2
1, -1
3, -1
Giải thích
a2 + b2 = 16 and 2ab = 7
To find all possible values = (a - b)2 + b2 - 2ab
Substituting the given values = (a - b)2
= 16 - 7
= 9
(a - b) = \(\pm\)9
= \(\pm\)3
OR a - b = 3, -3
To find all possible values = (a - b)2 + b2 - 2ab
Substituting the given values = (a - b)2
= 16 - 7
= 9
(a - b) = \(\pm\)9
= \(\pm\)3
OR a - b = 3, -3