Question 678301


{{{25c^2 + 5c -42}}}......replace {{{5c}}} with {{{-30c+35c}}}

{{{25c^2 -30c+35c -42}}}.........group


{{{(25c^2 -30c)+(35c -42)}}}


{{{5c(5c -6)+7(5c -6)}}}


{{{(5c+7)(5c -6)}}}....now you can set expression equal to zero an find solutions for {{{c}}}


{{{(5c+7)(5c -6)=0}}}

if {{{5c+7=0}}}.....=>....{{{5c=-7}}}...=>....{{{c=-7/5}}}

or

if {{{5c -6=0}}}.....=>....{{{5c=6}}}...=>....{{{c=6/5}}}