Evaluate the following when $a = 3$ , $b = \frac14$, and $c = 5$ :
\[
\frac{b^{-1}}{ca^{-1} - ac^{-1}}.
\]
b^(-1)
______________ remember that a^-1 = 1/a
ca^(-1) - a(c)^-1
So we can write
[ 1/ (1/4) ]
________________ =
5(1/3) - 3(1/5)
[ 1 / (1/4) ]
__________
5/3 - 3/5
Evaluate numerator and denominator separately
1/ (1/4) = (1/1) /(1/4) = (1/1) * ( 4/1) = 4
5/3 - 3/5 common denominator = 15
25 / 15 - 9/15 = 16/15
So....we have
4
_______ =
(16/15)
(4/1)
______ =
(16/15)
(4/1) ( 15/16) = (4 * 15) / (1 * 16) = 60/16 = 15 / 4