How do you solve #\frac { r } { r - 1} + \frac { 3} { r ^ { 2} - 1} = \frac { 9} { r + 1}#?
1 Answer
Jul 22, 2017
Explanation:
Given:
#r/(r-1)+3/(r^2-1) = 9/(r+1)#
Note that:
#r^2-1 = (r-1)(r+1)#
So we can make this rational equation into a polynomial one by multiplying both sides by
#r(r+1)+3=9(r-1)#
which multiplies out to:
#r^2+r+3 = 9r-9#
Subtract
#0 = r^2-8r+12 = (r-6)(r-2)#
(found by finding a pair of factors of
So:
#r = 2" "# or#" "r = 6#
Note that neither of these values cause