Tentukan nilai 4x -3y +2z dari sistem persamaan linear betikut 3x+2y+4z=11 2x+z=3 X-y=-1 cara matrix

jawab

3x + 2y + 4z = 11
2x + z = 3 .............kali 4

3x+ 2y + 4z = 11
8x + 4z = 12 .....(-)
-5x + 2y  = - 1

-5x + 2y = - 1
x - y = - 1......(kali 2(

-5x + 2y = -1
2x - 2y = - 2....(+)
-3x = - 3
x =  1

x- y = -1
y  = x + 1
y = 2

2x+ z= 3
z= 3 - 2x
z = 3 - 2(1)
z = 3 - 2
z= 1

nilai 4x - 3y + 2z =
= 4(1)  - 3(2) + 2(1)
= 4 - 6 + 2
=  0

3x +2y +4z = 11
2x + z = 3
––––––––––
3x +2y +4z =11
8x +4z = 12
–––––––––– -
-5x +2y = -1
x - y = -1
-5x +2y = -1
2x -2y = -2
–––––––– +
-3x = -3
x = 1

cari y = x-y =-1
→ 1 -y = -1
→ y = 2

cari z= 2x +z = 3
→ 2 +z = 3
→ z = 1

cari 4x -3y +2z
= 4 -6 +2
= 0

jadi jawabannya 0