Question

Срочно нужна помощь помогите пожалуйста

Answer 1

просто нужно раскрыть скопки по формуле:
${(x + y)}^{2} = {x}^{2} + 2xy + {y}^{2}$
${( frac{7}{8} c - frac{4}{7} d )}^{2} = frac{49}{64} {c}^{2} - 2 times frac{7}{8} c times frac{4}{7} d + frac{16}{49} {d}^{2} = frac{49}{64} {c}^{2} - cd + frac{16}{49} {d}^{2}$

${(x - y)}^{2} = {x}^{2} - 2xy + {y}^{2}$
1)
${(3x - 8y)}^{2} = {(3x)}^{2} - 2(3x)(8y) + {(8y)}^{2} = 9 {x}^{2} - 48xy + 64 {y}^{2}$
2)
${(7z + 11d)}^{2} = 49 {z}^{2} + 154zd + 121 {d}^{2}$
${(3.5t - 4k)}^{2} = 12.25 {t}^{2} - 28tk + 16 {k}^{2}$