High School

1) Find the logarithm of the following:
a) log_2(8)
b) Simplify: log(4) + log(5)
c) Solve for x: log^2(x) = 5
d) Find log_5(125)^4

Answer :

Let's solve each part of the question step by step:


  1. Find the logarithm of the following:


a) [tex]\log_2(8)[/tex]

To solve [tex]\log_2(8)[/tex], we need to find the power to which 2 must be raised to get 8. Since [tex]8 = 2^3[/tex], it follows that:

[tex]\log_2(8) = 3[/tex]

b) Simplify: [tex]\log(4) + \log(5)[/tex]

This expression can be simplified using the logarithm property that states [tex]\log_b(m) + \log_b(n) = \log_b(m \times n)[/tex]. Therefore:

[tex]\log(4) + \log(5) = \log(4 \times 5) = \log(20)[/tex]

c) Solve for [tex]x[/tex]: [tex](\log(x))^2 = 5[/tex]

First, take the square root of both sides to find [tex]\log(x)[/tex]:

[tex]\log(x) = \sqrt{5} \quad \text{or} \quad \log(x) = -\sqrt{5}[/tex]

Now, solve for [tex]x[/tex] by rewriting each expression in exponential form:

[tex]x = 10^{\sqrt{5}}[/tex] and [tex]x = 10^{-\sqrt{5}}[/tex]

Thus, [tex]x[/tex] can be either [tex]10^{\sqrt{5}}[/tex] or [tex]10^{-\sqrt{5}}[/tex].

d) Find: [tex]\log_5(125)^4[/tex]

First, calculate [tex]\log_5(125)[/tex]:

Since [tex]125 = 5^3[/tex], it follows that:

[tex]\log_5(125) = 3[/tex]

Now, let's find [tex]\log_5(125)^4[/tex]:

Multiply the result by 4:

[tex](\log_5(125))^4 = (3)^4[/tex]

Therefore, [tex]\log_5(125)^4 = 81[/tex]