Question

What is the approximate value of x in the equation below? log5(15)=x+3 –2.523 –1.317 2.880 7.485

Answer 1

Answer:

The value of x is -1.371(approximate)

b.

Step-by-step explanation:

Answer 2

Answer:

Option B is correct.

The value of x is -1.371(approximate)

Explanation:

Given equation: $\log_5 15$ =x+3

Using logarithmic rule:

$\log_{10} (ab) =\log_{10} a +\log_{10} b$

$\log_b b =1$

We can write $\log_5 15$ as;

$\log_5 15 =\log_5 (5\times 3) = \log_5 5 +\log_5 3$  

$\log_5 15 = 1 +\log_5 3$                 [using logarithmic rule]

By graphing calculator the value of $\log_5 3$ = 0.682606194486.

then, we have

$\log_5 15 = 1 +0.682606194486 =1.682606194486$

substitute this value in [1] to solve for x;

$1.682606194486 =x+3$

Subtract 3 from both sides we have,

$1.682606194486-3 =x+3-3$

Simplify:

-1.31739381 =x or

x =-1.317 (approx.)

Therefore, the approximate value of x is : -1.317