First factor the each term in the expression.

2x =  2 · x 

4y =  2 · 2 · y

16 =  2 · 2 · 2 · 2

The GCF is the product of the common prime factors in each term.

GCF = 2

Write each term as a product of the GCF and its remaining factors.

2x + 4y - 16 = 2(x) +2( 2y) - 2(8) \ \

Combine like terms uisng distribuitve property: ab + ac = a(b + c).

2x + 4y - 16 = 2(x + 2y - 8)

Simplified expression is 2(x + 2y - 8) .