Question

please solve this its urgent please friends ​

Answer 1

Answer:

$1.3 {x}^{2} + {4}^{2} - 2 \times 3x \times 4 \\ 9 {x}^{2} + 16 - 24x \\ 3. {5x}^{2} - {4y}^{2} \\ 25 {x}^{2} - 16 {y}^{2}$