Question

Nilai z yang memenuhi matriks pada gambat dibawah adalah

Answer 1

2x-y = -7 (x6) --> 12x-6y = -42
5x-6y = -21 (x1) --> 5x-6y = -21 _
                                 7x = -21 --> x=-3
2.(-3)-y = -7
-y = -7 + 6
-y = -1
y = 1

-2x+5y = 2z-1
-2.(-3)+5(1) = 2z-1
6+5+1 = 2z
12 = 2z
z = 6

Answer 2

X-> 2x - y = -7
      5x - 6y = -21
=> 10x - 5y = -35 (dikalikan 5 seluruhnya)
      10x - 12y = -42 (dikalikan 2 seluruhnya)
=> (di eliminasi dengan di kurangi) = 7y = 7
=> y = 1
(di substitusi) 2x - 1 = -7
=> 2x = -6
x = -3

z-> -2x + 5y = 2z -1
=> -2.-3 + 5.1 = 2z -1
=> 6 + 5 = 2z -1
=> 11 + 1 = 2z
=> 2z = 12
=> z = 6