If 3x + 2y = 12 and xy = 6, then find the value of 9x² + 4y²
Answers
Answered by
51
(3x + 2y) ² = (12)²
Or, 9x² +12xy + 4y² = 144
Or, 9x² + 72 + 4y² = 144
Or, 9x² + 4y² = 144-72 = 72 (Ans)......
Or, 9x² +12xy + 4y² = 144
Or, 9x² + 72 + 4y² = 144
Or, 9x² + 4y² = 144-72 = 72 (Ans)......
dragonballAlex:
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Answered by
98
Hello..
Answer...
We have,
( 3x + 2y) ² = (3x) ² + (2y) ² + 2 × 3x × 2y
=> ( 3x + 2y) ² = ( 9x² + 4y² ) + 12xy
=> 12² = 9x² + 4y² + 12 × 6. ( putting 3x + 2y = 12 and xy = 6 )
=> 144 = 9x² + 4y² + 72
=> 144 - 72 = 9x² + 4y²
=> 9x² + 4y² = 72
Hope it helped ☺☺☺
Answer...
We have,
( 3x + 2y) ² = (3x) ² + (2y) ² + 2 × 3x × 2y
=> ( 3x + 2y) ² = ( 9x² + 4y² ) + 12xy
=> 12² = 9x² + 4y² + 12 × 6. ( putting 3x + 2y = 12 and xy = 6 )
=> 144 = 9x² + 4y² + 72
=> 144 - 72 = 9x² + 4y²
=> 9x² + 4y² = 72
Hope it helped ☺☺☺
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