Question

expand (-2a - 5b)² pls ​

Answer 1

$\sf \: {( - 2a \: - \: 5 \: b)}^{2} \\ \\ \sf \: ( - 2a \: - \: 5 \: b) \: ( - 2a \: - \: 5 \: b) \\ \\ \sf \: −2(−2−5)−5(−2−5) \\ \\ \sf \: 4 {a}^{2} +10−5(−2−5)$

Answer 2

Answer:

By algebraic equation

${(x + y)}^{2} = {x}^{2} + {y}^{2} + 2xy \\ {( - 2a - 5b)}^{2} = { (- 2a)}^{2} + {( - 5b)}^{2} + (2 \times - 2a \times -5b) \\ = 4 {a}^{2} + 25 {b}^{2} + 20ab$