Simplify the following: $(2x+y+5)(2x+y-9)$.

Simplify the following: $(x-2y-5)(x-2y+3)$.

Simplify the following: $(3x-4y-2)(3x-4y-6).$

Simplify the following$(x+\frac{1}{x})$$(x^2-1+\frac{1}{x^2})$

Simplify the following:$(x-\frac{3}{x})$$(x^2+3+\frac{9}{x^2})$

Simplify the following: $(2x+3y+4z) (4x+9y+16z-6xy-12yz-8zx).$

Find the product of the following: $(x+1)(x+2)(x+3).$

Find the product of the following $(x-2)(x-3)(x+4)$.