Here is your answer
[tex]{(3c - 5)}^{2} - {16c}^{2} [/tex]
[tex] = {(3c - 5)}^{2} - {(4c)}^{2} [/tex]
[tex]using \: identity \\ {a}^{2} - {b}^{2} = (a + b)(a - b)[/tex]
[tex](3c - 5 + 4c)(3c - 5 - 4c)[/tex]
[tex](7c - 5)( - c - 5)[/tex]
HOPE IT IS USEFUL
