S suphukaman New member Xu 0 7/9/11 #1 :haha: 1. \[2^{x-1} - 3^x = 3^{x-1} - 2^{x+2}\] 2. \[9^x + 6^x = x.4^x\] Sửa lần cuối bởi điều hành viên: 7/9/11
light_future96 New member Xu 0 8/9/11 #2 \[1.{2}^{x-1}-{3}^{x}={3}^{x-1}-{2}^{x+2}\] \[\Leftrightarrow {2}^{x-1}-{3}^{x-1}.3={3}^{x-1}-{2}^{x-1}.8\] \[\Leftrightarrow {3}^{2}.{2}^{x-1}={2}^{2}.{3}^{x-1}\] \[\Leftrightarrow {2}^{x-3}={3}^{x-3}\] \[\Leftrightarrow x-3=0\] \[\Leftrightarrow x=3\]
\[1.{2}^{x-1}-{3}^{x}={3}^{x-1}-{2}^{x+2}\] \[\Leftrightarrow {2}^{x-1}-{3}^{x-1}.3={3}^{x-1}-{2}^{x-1}.8\] \[\Leftrightarrow {3}^{2}.{2}^{x-1}={2}^{2}.{3}^{x-1}\] \[\Leftrightarrow {2}^{x-3}={3}^{x-3}\] \[\Leftrightarrow x-3=0\] \[\Leftrightarrow x=3\]