How do you solve 2^x = 3^(x-1) 2x=3x1?

1 Answer
Dec 11, 2015

x=log_(2/3)3x=log233

Explanation:

color(white)(xxx)2^x=3^(x-1)×x2x=3x1

=>log_3 2^x=x-1log32x=x1

The logarithm of the x^(th)xth power of a number is xx times the logarithm of the number itself:
color(white)(xxx)xlog_3 2=x-1×xxlog32=x1

Multiply both sides by color(red)(1/x)1x
color(white)(xxx)color(red)(1/x*)xlog_3 2=color(red)(1/x*)(x-1)×x1xxlog32=1x(x1)
=>(x-1)/x=log_3 2x1x=log32

Add color(red)(-1)1 to both sides:
color(white)(xxx)(x-1)/xcolor(red)(-1)=log_3 2color(red)(-1)×xx1x1=log321
=>1/x=log_3 2-11x=log321
=>1/x=log_3 2-color(blue)(log_3 3)color(white)(xxxxx)1x=log32log33××x (because for AAainRR, a^1=a)

The logarithm of the ratio of two numbers is the difference of the logarithms:
=>1/x=log_3 (2/3)
=>x=log_(2/3)3