Question

Solve the exponential equation. 125^7x-2 = 150.

A.) -0.1375
B.) 2.1483
C.) 0.4234
D.) 0.4340

Answer 1

D.) -0.1375

Explanation:

Answer 2

D

Explanation:

You need to get the x out of the position in which is currently sitting, which is exponential. The only way to get an exponent out from that position is to take the log of both sides. The power rule of logs allows us to move the exponent down in front of the log. Like this:

7x - 2 log (125)=log(150)

Now you want to divide both sides by log(125) to get the 7x - 2 all by itself:

`7x-2=(log(150))/(log(125))`

Do that on your calculator and you'll get this:

7x - 2 = 1.037760918

Add 2 to both sides to get

7x = 3.037760918

then divide both sides by 7:

x = .4339 which rounds to .4340