Factorise: $x^2+8x+16$x2+8x+16
Factorise: $x^2+16x+64$x2+16x+64
Factorise: $x^2-4x+4$x2−4x+4
Factorise: $x^2-20x+100$x2−20x+100
Factorise where possible expressions of the form: a^2x^2 – b^2y^2, a^2 + 2ab + b^2, ax^2 + bx + c.