Question

Rozwiąż układ równań

{1/5( 6x + 14y) = 3x + 0,8 /*5
{7+2* (20x + y)/ 7 = y -(7x + 6/7) /*7

Answer 1

1/5( 6x + 14y) = 3x + 0,8 /*5
7+2* (20x + y)/ 7 = y -(7x + 6/7) /*7

6x+14y=15x+4
49+2(20x+y)=7y-7(7x+6/7)

6x-15x=4-14y
49+40x+2y=7y-49x-6

-9x=4-14y /*(-1)
40x+2y+49x-7y=-6-49

9x=14y-4
89x-5y=-55

x=(14/9)y-4/9
89[(14/9)y-4/9]-5y=-55

x=(14/9)y-4/9
89[(14/9)y-4/9]-5y=-55

x=(14/9)y-4/9
1246/9y-356/9-5y=-55

x=(14/9)y-4/9
1201/9 y=-139/9

x=(14/9)y-4/9
y=-139/1201

x=(14/9)*(-139/1201)-4/9
y=-139/1201

x=-750/1201
y=-139/1201

x≈-0,12
y=-0,62