Answer:
[tex]k(x)=(x-4)(x+6)[/tex]
Step-by-step explanation:
[tex]k(x)=(x+1)^2-25\\\\[/tex]
to factorize it you have to remember the difference of squares that says
[tex]a^2-b^2=(a-b)(a+b)[/tex]
so we have
[tex](x+1)^2\\\\(x+1)^2=a^2\\\\25\longrightarrow 5^2\\\\5^2=b^2\\\\[/tex]
and we apply the formula
[tex](x+1)^2-25=[(x+1)-5][(x+1)+5]\\\\=(x+1-5)(x+1+5)\\\\=(x-4)(x+6)[/tex]
so there you have it
[tex]k(x)=(x-4)(x+6)[/tex]