Question

4x+5y=-62 .....(1)
3x-2z=-15.....(2)
4y+z=-37.....(3)

Himpunan penyelesaian dari sistem persamaan tersebut adalah....

Jawab beserta cara ya

Answer 1

(1) 4x + 5y = -62
(2) 3x - 2z = -15
(3) 4y + z = -37

4x + 5y = -62 (x3)
3x - 2z = -15 (x4)
__________________
12x + 15y = -186 »» 12x = -15y -186
12x - 8z = -60 »» 12x = 8z -60
___________________
-15y -186 = 8z -60 »» -15y - 8z = 186 - 60
»» -15y -8z = 126 (persamaan 4)

-15y -8z = 126 (x1)
4y + z = -37 (x8)
________________
-15y -8z = 126
32y+8z = -296
_____________ +
17y = -170
y = -10

4y+z = -37
4 (-10) + z = -37
z = -37 + 40
z = 3

3x - 2z = -15
3x -2 (3) = -15
3x = -15 + 6
3x = -9
x = -3

jadi
x = -3
y = -10
z = 3