Question

СРОЧНО напишите решение ПОДРОБНО
номера 1,2и 7

Answer 1

1)
$4x + y = 2y - 4 \ 3x + y = x + 1 \ \ 4x + y - 2y = - 4 \ 3x - x + y = 1 \ \ 4x - y = - 4 \ 2x + y = 1 \ \ 6x = - 3 \ y = 1 - 2x \ \ x = - 0.5 \ y = 1 - 2x\ \ x = - 0.5 \ y = 1 - 2 times ( - 0.5 )= 1 + 1 = 2$
Ответ: (-0,5; 2)

2)
$f(4) = frac{ {4}^{2} - 2 times 4 - 8}{ 4 + 2} = frac{0}{6} = 0 \ \ f(0) = frac{ {0}^{2} - 2 times 0 - 8 }{0 + 2} = frac{ - 8}{2} = - 4 \ \ f(3) = frac{ {3}^{2} - 2 times 3 - 8 }{3 + 2} = frac{ - 5}{5} = - 1 \ \ 3f(4) - f(0) + 2f(3) = 3 times 0 - ( - 4) + 2 times ( - 1) = 4 - 2 = 2$
Ответ: 2.


7)
$(a - b)( {a}^{2} + ab + {b}^{2} ) + b {(a - b)}^{2} - a(a - b)(a + 2b) = {(a - b)}^{3} + b {(a - b)}^{2} - a(a - b)(a + 2b) = (a - b)( {(a - b)}^{2} + b(a - b) - a(a + 2b)) = (a - b)( {a}^{2} - 2ab + {b}^{2} + ab - {b}^{2} - {a}^{2} - 2ab) = (a - b)( - 3ab) = - 3 {a}^{2} b + 3a {b}^{2}$