Question

Please answer asap...​

Answer 1

Answer:

$9 {x}^{2} + 16 {y}^{2} + 49 {z}^{2} \\ - 28xy - 56yz + 42zx$

Step-by-step explanation:

${(3x)}^{2} + {( - 4y)}^{2} + {(7z)}^{2} \\+ 2 \times 3x \times - 4y + 2 \times - 4y \times 7z + \\ 2\times 7z \times 3x$

$9 {x}^{2} + 16 {y}^{2} + 49 {z}^{2}\\ - 28xy - 56yz + 42zx$