Solve the following equations. Be accurate to three decimal places. Be sure to check your answers.

1. $7 = 4.2^{x}$

   Hint (a):

   $\operatorname{ln} 7 = x \operatorname{ln} 4.2$

   Answer (a):

   $1.356$

2. $3x^{5} = 126$

   Answer (b):

   $x=\sqrt[5]{42}$

3. $14 = 2 · 4^{x}− 10$

   Hint (c):

   See part (a).