Final answer:
When substituting x=3 and y=6 into the expression (2x+4xy)(-y-8), it simplifies to 78*(-14), which equals -1092.
Step-by-step explanation:
To evaluate the expression (2x+4xy)(-y-8) when x=3 and y=6, we first substitute the given values into the expression:
(2×3+4×3×6)(-6-8)
Now, we calculate the expression inside the parenthesis:
(6+4×18)(-14)
(6+72)(-14)
(78)(-14)
Next, we multiply the two numbers:
78×(-14) = -1092
Therefore, the value of the expression when x=3 and y=6 is -1092.