6. Given the function \( f ( x ) = \frac { 2 } { 3 } x - 5 \) , evaluate \( f ( 9 ) \) . Hint: To type a fraction into a calculator, use the division button. \( 2 / 3 \) would be typed as \( 2 \) divided by \( 3\) .
\(- 2 \)
\( 1 \)
\( 11 \)
\( 6\)
7. Given the function \( h ( t ) = 2 t ^ { 2 } + 9 \) , evaluate \( h ( 5 )\) .
6. B OPTION
7. 59
Find the solution of the exponential equation \( 16 e ^ { x } = 12 \) in terms of logarithms, or correct to four decimal places. \( x = \)
Certain radioactive material decays in such a way that the mass remaining after \( t \) years is given by the function
\( m ( t ) = 100 e ^ { - 0.01 t } \)
where \( m ( t ) \) is measured in grams. (a) Find the mass at time \( t = 0 \) . Your answer is (b) How much of the mass remains after \( 20 \) years? Your answer is Round answers to \( 1 \) decimal place.
