Q. Find the numerical value of the log expression.loga=10logb=7logc=−6loga4b5cAnswer:
Apply Quotient Rule: Let's start by expressing the given logarithm using the properties of logarithms.We have the expression log(a4b5c).Using the quotient rule of logarithms, which states that log(ba)=log(a)−log(b), we can separate the numerator and the denominator.
Expand Numerator and Denominator: Now, we apply the quotient rule to the given expression: log(a4b5c)=log(c)−log(a4b5).
Simplify Using Rules: Next, we use the product rule of logarithms for the denominator, which states that log(a∗b)=log(a)+log(b), and the power rule, which states that log(an)=n⋅log(a), to further expand the expression:log(c)−(log(a4)+log(b5)).
Apply Power Rule: We can simplify the expression by applying the power rule to the terms log(a4) and log(b5), and recognizing that c is c21:log(c21)−(4log(a)+5log(b)).
Substitute Given Values: Now we apply the power rule to log(c21), which gives us 21⋅log(c):21⋅log(c)−(4⋅log(a)+5⋅log(b)).
Perform Arithmetic Operations: We substitute the given values for log(a), log(b), and log(c) into the expression:(21)∗(−6)−(4∗10+5∗7).
Combine Terms and Subtract: Perform the arithmetic operations: −3−(40+35).
Get Numerical Value: Combine the terms inside the parentheses and then subtract from −3:−3−75.
Get Numerical Value: Combine the terms inside the parentheses and then subtract from −3:−3−75.Finally, we get the numerical value of the expression:−3−75=−78.
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