a-b=3,a2+b2=17then find the valu of ab=
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Answered by
1
a-b =3
Squaring on both sides, we get
(a-b) ²=3²
a²-2ab+b² = 9
17-2ab =9 (since a²+b² =17)
17-9 = 2ab
2ab = 8
ab = 8/2
ab = 4
Squaring on both sides, we get
(a-b) ²=3²
a²-2ab+b² = 9
17-2ab =9 (since a²+b² =17)
17-9 = 2ab
2ab = 8
ab = 8/2
ab = 4
Answered by
2
Hi Friend ✋✋
a - b = 3
a = 3 + b..........(1)
a² + b² = 17
From (1)
( 3 + b )² + b² = 17
9 + 6b + b² + b² = 17
2b² + 6b - 8 = o
2b² + 8b - 2b - 8 = 0
2b × ( b + 4 ) - 2 × ( b + 4 ) = 0
( 2b - 2 ) ( b + 4 ) = 0
Therefore b = 1 , -4
When b = 1
a = 3 + 1 = 4
then ab = 4 × 1 = 4
When b = -4
a = 3 - 4 = -1
then ab = -1 × 1 = -1
hope it helps
a - b = 3
a = 3 + b..........(1)
a² + b² = 17
From (1)
( 3 + b )² + b² = 17
9 + 6b + b² + b² = 17
2b² + 6b - 8 = o
2b² + 8b - 2b - 8 = 0
2b × ( b + 4 ) - 2 × ( b + 4 ) = 0
( 2b - 2 ) ( b + 4 ) = 0
Therefore b = 1 , -4
When b = 1
a = 3 + 1 = 4
then ab = 4 × 1 = 4
When b = -4
a = 3 - 4 = -1
then ab = -1 × 1 = -1
hope it helps
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