А)
2x - 6y - 3 = 15 2x - 6y = 18 (:2) x - 3y = 9 x = 9+3y x=9+3y
3x+3+3y = 2y - 2 3x + y = - 5 3x + y =-5 3(9+3y)+y = -5 27+9y+y = -5
x=9+3y x =9+3y x=9-9,6 x= -0,6
10y= -32 y =-3,2 y= - 3,2 y= - 3,2
б)
5(2x+1)+7(2y+2) =7 10x+5+14y+14 =7 10x+14y = -12 (:2) 5x+7y = -6 5x+7y = -6
2(3x-2)+y+4 =16 6x-4+y+4 =16 6x+y = 16 6x+ y = 16 y= 16 - 6x
5x+7(16-6x)= -6 5x+112-42x = -6 37x = 118 x = 118/37 =3 7/37
y= 16 - 6x y= 16 - 6x y= 16- 6x y= 16- 18 42/37 = 16 - 19 5/37 = -3 5/37