If 9x 2 + 25y 2 =181 and xy= -1 find the value of 3x+5y.
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Answer:
( 3x + 5y ) = √151
Step-by-step explanation:
Given :
9x² + 25y² = 181
xy = - 1
We know that
( a + b )² = a² + b² + 2ab
Therefore,
( 3x + 5y )² = (3x)² + (5y)² + 2.3x.5y
= 9x² + 25y² + 30xy
= 181 + 30 ( -1 )
= 181 - 30
= 151
As ( 3x + 5y )² = 151
so, ( 3x + 5y ) = √151
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