How do you solve log_(6)x + log_(6)3 = 2log6x+log63=2?

1 Answer
Jun 11, 2018

x=12x=12

Explanation:

We can start by subtracting log_6(3)log6(3) from both sides. This gives us

log_6x=color(darkviolet)(2-log_6(3))log6x=2log6(3)

We can apply the logarithm rule

a=log_b(b^a)a=logb(ba)

where our aa is what I have in purple above. This can be rewritten as

log_6x=color(darkviolet)(log_6(ul(6^(2-log_6(3))))

Let's simplify what I have underlined:

6^(2-log_6(3)) can be rewritten as

6^(-log_6(3))*6^2

Which simplifies to

3^-1*color(blue)(6^2)

Further simplifying, we get

1/3*color(blue)(36)=36/3=color(darkviolet)(12)

Remember, this is the underlined portion of our equation. We have

log_6x=color(darkviolet)(log_6(12))

Since the bases are the same, we now have

x=12

All we did was:

  • Subtract to get logs on both sides
  • Rewrite the expression in a form we can deal with
  • Simplify the expression using many exponent properties
  • Realized that the bases are the same, so they basically cancel

Hope this helps!