Question 269830
step 1 - expand to get
{{{9f^2 -6f + 1 + 15f = 5}}}
combine like terms to get
{{{9f^2 + 9f + 1 = 5}}}
set = 0 to get
{{{9f^2 + 9f - 4 = 0}}}
factoring we get
 {{{(3f-1)(3f+4) = 0}}}
solving for f, we get
f = 1/3
or
f = -4/3