Question

Помогите пожалуйста с алгеброй

Answer 1

Ответ:

1)

${(11a - b)}^{2} + (9a + 7b)(8a - 13b) = \\ = {(11a)}^{2} - 2 \times 11ab + {b}^{2} + 72 {a}^{2} - 117ab + 56ab - 91 {b}^{2} = \\ = 121 {a}^{2} - 22ab + {b}^{2} + 72 {a}^{2} - 91 {b}^{2} - 61ab = \\ = 193 {a}^{2} - 83ab - 90 {b}^{2}$

2)

$(18x + 5y)(2x - 4y) - {(6x - 3y)}^{2} = \\ = 36 {x}^{2} - 72xy + 10xy - 20 {y}^{2} - 36 {x}^{2} + 36xy - 9 {y}^{2} = \\ = - 26xy - 29 {y}^{2}$

Answer 2

1)(121a^2-22ab+b^2)+(72a^2-117ab+56ab-91b^2)=121a^2-22ab+b^2+72a^2–117ab+56ab-91b^2=193a^2-90b^2-83ab
2)(36x^2-72xy+10xy-20y^2)-(36x^2-36xy+9y^2)=36x^2-72xy+10xy-20y^2-36x^2+36xy-9y^2=-29y^2-26xy