Question

(c+2)(c-2)-(5c^2-b^2)​

Answer 1

$(c + 2)(c - 2) - (5c {}^{2} - b {}^{2} ) = c {}^{2} - 4 - 5c {}^{2} + b {}^{2} = b {}^{2} - 4c {}^{2} - 4$