Question 470759
{{{e^(x + 15) - e^x = 4}}}
Use property of exponent addition: {{{x^2*x^3 = x^(2+3)}}}
{{{e^x*e^15 - e^x = 4}}}
Factor out e^x
{{{(e^x)(e^15 - 1) = 4}}}
Divide by e^15 - 1 on both sides
{{{e^x = 4/(e^15 - 1)}}}
Take Natural Log of both sides
{{{x = ln (4/(e^15 - 1)) = -13.61}}}