Question

Jika diketahui3^x^-2y=1per81 dan 2^x^-y=16 maka nilai x+y=

Tolong di jawab ya, soalnya buat belajar uts nnti

Answer 1

3^(x-2y)  = 1/81
3^(x-2y) = 3^(-4)
x - 2y = -4 ...(1)
.
2^(x-y) = 16
2^(x-y) = 2^4
x- y = 4 ....(2)
..
(1) dan (2) eliminasi
x - 2y = -4
x  - y = 4
......(-)......
-y = -8
y = 8 
.
x - y = 4
x = y + 4
x = 8+4
x = 12
.
x+y = 12+8 
x +y= 20