Please help me and include step by step!!!(x+9)(x-9) Polynomial identities

Answer:The given expression is simplified as [tex](x + 9)(x -9)  = x^{2}   - 81[/tex]Step-by-step explanation:Here,the given expression is (x+9)(x -9)Using the ALGEBRAIC IDENTITY:[tex](a +b)(a -b)  = a^2  - b^2[/tex]Now, here in the given expression (x + 9)(x -9)Comparing it the left side of the identity, we get  a  =  x     and  b = 9The right side of the equation is [tex]a^{2}   - b^{2}[/tex]Substituting the value of a and b, we get⇒ [tex](x + 9)(x -9)  =   (x)^{2}   - (9)^{2}[/tex]= [tex]x^{2}   - 81[/tex]Hence, the given expression is simplified as [tex](x + 9)(x -9)  = x^{2}   - 81[/tex]