14. If 3x + 4y = 16 and xy = 4; find the value,
9.x2 +
16y2
S
Answers
Answered by
6
Answer:
160
Step-by-step explanation:
= > 3x + 4y = 16
Square on both sides:
= > ( 3x + 4y )^2 = 16^2
Using ( a + b )² = a² + b² + 2ab
= > ( 3x )^2 + ( 4y )^2 + 2( 3x * 4y ) = 256
= > 9x² + 16y² + 24xy = 256
= > 9x² + 16y² + 24(4) = 256
= > 9x² + 16y² + 96 = 256
= > 9x² + 16y² = 256 - 96
= > 9x² + 16y² = 160
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