Question

Jika x dan y memenuhi persamaan 2^4x-7y-7 = 4^x + 3y dan 27^x-y = 3^2x-7 maka y-x =

Answer 1

4x-7y-7 = 2(x+3y)
4x-7y-7 = 2x+6y
2x-13y = 7  pers 1.



3(x-y) = 2x-7
3x-3y = 2x-7
x = 3y-7 pers 2

pers 2 disubstitusikan ke pers 1.

2x-13y = 7
2(3y-7) - 13y = 7
6y - 14 - 13y = 7
-7y = 21
y = -3

x = 3y-7
   = 3(-3) -7
x = -16

∴ y-x = (-3) - (-16) = 13