Cari nilai x, y, z dari: a. x + y = 470 -x + z = 685 -y + 2z = 630 b. x + y + z = 11 -2x + y + 3z = 12 5x - 2z = 1

a. x + y = 470
-x + z = 685
-y + 2z = 630

x + y = 470
-x + z = 685
--------------- +
y + z = 1155

y + z = 1155
-y + 2z = 630
--------------- +
3z = 1785
z = 595

y + z = 1155
y + 595 = 1155
y = 1155 - 595
y = 560

x + y = 470
x + 560 = 470
x = 470 - 560
x = -90

jadi nilai x = -90, y = 560, dan z = 595

b. x + y + z = 11
-2x + y + 3z = 12
5x - 2z = 1

x + y + z = 11
-2x + y + 3z = 12
--------------- -
3x - 2z = -1

3x - 2z = -1
5x - 2z = 1
--------------- -
-2x = -2
x = 1

3x - 2z = -1
3 - 2z = -1
-2z = -1 - 3
-2z = -4
z = 2

x + y + z = 11
1 + y + 2 = 11
3 + y = 11
y = 8

jadi nilai x = 1, y = 8, dan z = 2

semoga membantu :)