Question

Решите систему уровнений способом сложения :
Даю 60 баллов . Заранее спасибо !!!

Answer 1

[3]
(x+7)/4 + (y-5)/2 =-1 <=> x +7 +2y -10 +4 =0 <=> x +2y +1 =0
(x+10)/3 - (y+8)/5 =4 <=> 5x +50 -3y -24 -60 =0 <=> 5x -3y -34 =0

5x +10y +5 =0
5x -3y -34 =0
-------------
13y +39 =0 <=> y= -39/13 = -3

x -6 +1 =0 <=> x= 5

[4]
(x-9)/3 - (y+10)/2 =0 <=> 2x -18 -3y -30 =0 <=> 2x -3y -48 =0
(x-7)/4 + (y+10)/8 =-1,5 <=> 2x -14 +y +10 +12 =0 <=> 2x +y +8 =0

2x +y +8 =0
2x -3y -48 =0
-------------
4y +56 =0 <=> y= -14

2x -14 +8 =0 <=> x= 3