(c+d)^2+11(c+d)+30

Factor completely.

firstable give c+b a polynomial value like x

so its will be x^2+11x+30

after the we have to factor it

30=6×5

and 11=6+5

so its will become

(x+6)×(x+5)=x^2+11x+30

x=c+d

(c+d+6)×(c+d+5)=(c+d)^2+11(c+d)+30

have a great day