Question

Diket sistem persamaan 2x-3y = -18 dan 4x-y = -16 nilai. 5x + 2y

Answer 1

2x - 3y = -18   ..........dikali 2
4x - y   = -16

menjadi :
4x - 6y = -36
 4x - y   = -16   -
     -5y = -20
         y = -20/-5
          y = 4

subtitusi nilai y
4x - y   = -16
4x - 4  = -16
4x   = -16 + 4
  x   = -12/4
   x  = -3

maka nilai 
5x + 2y = 5(-3) + 2(4) = -15 + 8 = -7