diketahui sistem persamaan 4x-y+3z=-20.....(1) 3x+y+2z = -20....(2) 2x+4y+3z =-25....(3) jika penyelesaian SPLTV tersebut (a,b,c)nilai a-b-c =... Sertakan Cara

4x - y + 3z = -20
3x + y + 2z = -20
______________ +
7x + 5z = -40 .... (4)

3x + y + 2z = -20 (×4) 》12x + 4y + 8z = -80
2x + 4y + 3z = - 25 (×1) 》2x + 4y + 3z = - 25
_______________ _
10x + 5z = -55 ..... (5)
pers (4) dan (5)
7x + 5z = -40
10x + 5z = -55
____________ _
-3x = 15
x = -3

10x + 5z = -55
10(-3) + 5z = -55
5z = 25
z = 5

3x + y + 2z = -20
3(-3) + y + 2(5) = -20
y = -20+9-10
y = -21
HP { (-3,-21,5)}