Question

1. dengan metode eliminasi , tentukan penyelesaian dari :
a ) 4x + y - 3z = 11
2x - 3y + 2z = 9
x + y + z = -3

b) 2x - 5y + 3z = 10
3x + 4y + 7z = -11
5x + 3y + 7z = -8
tolong banget jawabin yaah

Answer 1

A)
eliminasikan  y
4x + y - 3z = 11
x + y +  z = -3
-------------------(-)
3x - 4z = 14 ....(1)

eliminasikan y
2x - 3y + 2z = 9
x + y + z = - 3 .......(kalikan 3)
.
2x - 3y + 2z = 9
3x - 3y + 3z = - 9
--------------------(-)
-x  - z = 18 ...(2)
.
(1) dan (2) eliminasikan x
3x - 4z = 14
-x -  z = 18....kalikan 3
....
3x - 4z = 14
-3x - 3z = 54
------------------(+)
-z = 68
z = - 68
.
3x - 4z = 14
3x - 4(- 68) = 14
3x = -258
x = -86
.
x + y +z = - 3
-86 +y - 68 = - 3
y = 151
.
(x, y, z) = (-86, 151 ,  68)