20X - 15Y = 35 (:5)
4X - 3Y = 7
X = 1/4*(3Y + 7)
5*(1/4*(3Y+7) - 4Y = 10
15/4Y + 35/4 - 16/4Y = 40/4
-Y = 5
Y = - 5
X = 1/4*(-15 +7) = 1\4*(-8) = - 2
ответ: Х = - 2 ; Y = - 5
15х-11у=25
5х-4у=10 (-3)
+{15х-11у=25
+{-15х+12у=-30
у=-5
15х-11(-5)=25
15х+55=25
15х=25-55
15х=-30
х=-2
ответ:(-2;-5)
20X - 15Y = 35 (:5)
4X - 3Y = 7
X = 1/4*(3Y + 7)
5*(1/4*(3Y+7) - 4Y = 10
15/4Y + 35/4 - 16/4Y = 40/4
-Y = 5
Y = - 5
X = 1/4*(-15 +7) = 1\4*(-8) = - 2
ответ: Х = - 2 ; Y = - 5
15х-11у=25
5х-4у=10 (-3)
+{15х-11у=25
+{-15х+12у=-30
у=-5
15х-11(-5)=25
15х+55=25
15х=25-55
15х=-30
х=-2
ответ:(-2;-5)