Question

решите данное системное уравнение                                                                                     1){x+y=1   x-y=5} ;     2) {2х-7у=39  х+у=-3} ;                                                                                                                                                                                                                                                                                               3) {5х-2у=-12   3х+4у=-2} ;                                                                                                                 4) {х+2у=5    -х+7у=13} решите и сфоткайте!!!Срочно надо!!!!

Answer 1

1) x+Y=1
X-Y=5
2x=6
X=3
Y=-2
Ответ: (3;-2)

2) 2x-7y=39
x+Y=-3 |•7

2x-7y=39
7x+7y=-21

9x=18
X=2
Y=-5

Ответ: (2;-5)

5x-2y=-12|•2
3x+4y=-2

10x-4y=-24
3x+4y=-2

13x=-26
X=-2
Y=1
Ответ: (-2;1)

x+2y=5
-x+7y=13
9y=18
Y=2
X=1

ответ: (1;2)