Question

14. If 3x + 4y = 16 and xy = 4; find the value,
9.x2 +
16y2
S​

Answer 1

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