Question

factor by introducing an appropriate substitution (x+2)^2+12(x+2)+35

Answer 1

Let y = x + 2 then the quadratic expression becomes:
y^2 + 12y + 35

Answer 2

my question also says let u=x=2

Answer 3

You can set x + 2 equal to any variable you want. The key is to get it in an appropriate form for factoring.