Нужно срочно пж алгебра

Объяснение:

1,а)

$1)4x - 9y = 3 \\ 2)x = 6 - 3y \\ 4 \times (6 -3y) - 9y = 3 \\ y = 1 \\ x = 6 - 3 \times 1 \\ x = 3 \\ (x.y) = (3.1) \\ proverim \\ 1)4 \times 3 - 9 = 3 \\ 2)3 + 3 \times 1 = 6 \\ (x.y)(3.1)$

$1)8x - 6y = 14 \\ 2)2x + 3y = - 1 \\ 1)4x - 3y = 7 \\ 2)2x + 3y = - 1 \\ 4x - 3y + 2x + 3y = 7 - 1 \\ 6x = 6 \\ x = 1 \\ 2 \times 1 + 3y = - 1 \\ y = - 1 \\ (x.y)(1. - 1) \\ proverim \\ 1)8 \times 1 - 6 \times ( - 1) = 14 \\ 2)2 \times 1 + 3( - 1) = - 1 \\ 1)14 = 14 \\ 2) - 1 = - 1 \\ (x.y)(1. - 1)$

х- мальчики

у- девочек

тогда просим систему уравнений :

$1)x + y = 23 \\ 2)3x + 4y = 83 \\ 1)x = 23 - y \\ 2)3x + 4y = 83 \\ 3 \times (23 - y) + 4y = 83 \\ y = 14 \\ x = 23 - 14 \\ x = 9 \\ (x.y)(9.14) \\ proverim \\ 1)9 + 14 = 23 \\ 2)3 \times 9 + 14 \times 3 = 83 \\ 1)14 = 14 \\ 2)83 = 83 \\ togda \\ 14 \times 4 = 56 teyradey$