Solve each logarithmic equation in Exercises 49–92. Be sure to reject any value of x that is not in the domain of the original logarithmic expressions. Give the exact answer. Then, where necessary, use a calculator to obtain a decimal approximation, correct to two decimal places, for the solution. log(x+4)−log 2=log(5x+1)
Ch. 4 - Exponential and Logarithmic Functions

Capitolo 5, Problema 83
Evaluate or simplify each expression without using a calculator. log 107
Guida verificata passo dopo passo1
Recall the definition of logarithms: \(\log_b(a)\) asks the question, "To what power must the base \(b\) be raised to get \(a\)?"
In this problem, the base of the logarithm is 10, and the argument is \$10^7$, so we are looking for the exponent $x$ such that \(10^x = 10^7\).
Since the bases on both sides of the equation are the same (base 10), the exponents must be equal. Therefore, \(x = 7\).
Thus, \(\log 10^{7} = 7\) because the logarithm of a power of 10 with base 10 is simply the exponent.
This simplification uses the logarithmic identity: \(\log_b(b^k) = k\) for any positive base \(b \neq 1\) and any real number \(k\).

Risposta video verificata per un problema simile:
Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
1mConcetti chiave
Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.
Definition of Logarithms
A logarithm answers the question: to what exponent must the base be raised to produce a given number? For example, log_b(a) = c means b^c = a. Understanding this definition is essential for evaluating logarithmic expressions.
Video consigliato:
Logarithms Introduction
Logarithm of a Power
The logarithm of a number raised to an exponent can be simplified using the rule log_b(a^n) = n * log_b(a). This property allows you to bring the exponent in front as a multiplier, simplifying calculations without a calculator.
Video consigliato:
Powers of i
Common Logarithms (Base 10)
Common logarithms have base 10, written as log or log_10. Since log_10(10) = 1, powers of 10 simplify easily: log_10(10^n) = n. Recognizing this helps quickly evaluate expressions like log 10^7.
Video consigliato:
Graphs of Common Functions
Pratica correlata
Domanda del libro di testo
1283
views
Domanda del libro di testo
In Exercises 83–88, let logb 2 = A and logb 3 = C and Write each expression in terms of A and C.
logb (3/2)
819
views
Domanda del libro di testo
Use the formula for continuous compounding to solve Exercises 84–85. How long, to the nearest tenth of a year, will it take \$50,000 to triple in value at an annual rate of 7.5% compounded continuously?
649
views
Domanda del libro di testo
Expand:
797
views
Domanda del libro di testo
Evaluate or simplify each expression without using a calculator. 10log 33
894
views
Domanda del libro di testo
Solve each logarithmic equation in Exercises 49–92. Be sure to reject any value of x that is not in the domain of the original logarithmic expressions. Give the exact answer. Then, where necessary, use a calculator to obtain a decimal approximation, correct to two decimal places, for the solution. 2 log x−log 7=log 112
814
views
