Q. Given the function f(x)=−2x3+47x, find the value of f(23) in simplest form.Answer:
Substitute x into function: Substitute the value of x into the function.We are given f(x)=−2x3+47x and we need to find f(23). Let's substitute x=23 into the function.f(23)=−2(23)3+(47)(23)
Calculate cube of (23): Calculate the cube of (23).(23)3=(23)×(23)×(23)=827
Multiply by −2: Multiply the result by -2").\(\newline\$-2 \times \left(\frac{27}{8}\right) = -\frac{54}{8}\)
Simplify fraction \(-\frac{54}{8}\): Simplify the fraction \(-\frac{54}{8}\).\(-\frac{54}{8}\) can be simplified by dividing both the numerator and the denominator by \(2\).\(-\frac{54}{8} = -\frac{27}{4}\)
Multiply \((\frac{7}{4})\) by \((\frac{\(3\)}{\(2\)}): Multiply \((\frac{7}{4})\) by \((\frac{3}{2}).\(\newline\)\$(\frac{7}{4}) \times (\frac{3}{2}) = \frac{21}{8}\)
Add results: Add the two results together.\(\newline\)\(f\left(\frac{3}{2}\right) = -\frac{27}{4} + \frac{21}{8}\)\(\newline\)To add these two fractions, we need a common denominator. The common denominator for \(4\) and \(8\) is \(8\).
Convert \(-\frac{27}{4}\) to fraction: Convert \(-\frac{27}{4}\) to a fraction with a denominator of \(8\).\(-\frac{27}{4} = -\frac{27}{4} \times \frac{2}{2} = -\frac{54}{8}\)
Add fractions: Add the fractions with the common denominator.\(\newline\)\(f\left(\frac{3}{2}\right) = -\frac{54}{8} + \frac{21}{8}\)\(\newline\)\(f\left(\frac{3}{2}\right) = \frac{-54 + 21}{8}\)\(\newline\)\(f\left(\frac{3}{2}\right) = -\frac{33}{8}\)
More problems from Multiplication with rational exponents