Question

помогите плиз дам 40 баллов

Answer 1

$1) \: {(a + 7)}^{2} - 49 = {a}^{2} - 14a + 49 - 49 = {a}^{2} - 14a \\ 2) \: {(3x - 4y)}^{2} - 9 {x}^{2} = 9 {x}^{2} - 24xy + 16 {y}^{2} - 9 {x}^{2} = 16 {y}^{2} - 24xy \\ 3) \: {(x - 1)}^{2} - x(x - 2) = {x}^{2} - 2x + 1 - {x}^{2} + 2x = 1 \\ 4) \: {(6a - 7)}^{2} - {(4a - 3)}^{2} = 36 {a}^{2} - 84a + 49 - (16 {a}^{2} - 24a + 9) = 36 {a}^{2} - 84a + 49 - 16 {a}^{2} + 24a - 9 = 20 {a}^{2} - 60a + 40 \\ 5) \: {(3x - 2)}^{2} + (1 - 3x)(3x + 2) = 9 {x}^{2} - 12x + 4 + 3x + 2 - 9 {x}^{2} - 6x = - 15x + 6$