The answer for first equation: 8x + 16y is,
[tex]8(x + 2y)[/tex]
The answer for second equation: 12x - 16y is,
[tex]4(3x - 4y)[/tex]
The answer for the third equation: -6x - 8y is,
[tex] - 2(3x + 4y)[/tex]
Let me know if you need the explanation.
hope it helps.