3x-12 ≥7x+4
Subtract 3x from both sides
-12 ≥4x+4
Subtract 4 from both sides
-16 ≥4x
Divide each side by 4
-4 ≥x
From point 4, you use a closed circle and the arrow is facing towards 0
Answer:

Step-by-step explanation:
The function that could model this periodic phenomenon will be of the form

The tide varies between 3ft and 9ft, which means its amplitude
is

and its midline
is
.
Furthermore, since at
the tide is at its lowest ( 3 feet ), we know that the trigonometric function we must use is
.
The period of the full cycle is 14 hours, which means


giving us

With all of the values of the variables in place, the function modeling the situation now becomes

5/3 each friend gets 3/5 of the trail mix
k-4/3= 3
Mutiply both sides by 3 .
(3)(k-4/3)= (3)(3)
Cross out 3 and 3 , divide by 3 and then becomes k-4= 9
Move -4 to the other side
Sign changes from -4 to +4
k-4+4= 9+4
k= 13
Answer: k= 13