Answer:
Mark still owes $24
Step-by-step explanation:
53-29=24
He buyed 240 cards because
20
x
12
-----
40
+
20
-------
240
Answer:
-3a-4b+5
Step-by-step explanation:
(3a-6b+12)-(6a-2b+7)
3a-6b+12-6a+2b-7
3a-6a-6b+2b+12-7
-3a-4b+5
Sin angle that equals the 1/2 value is the 30 degree on the 1st Quadrant.
The angle of 30 degree on the 3rd Quadrant is equivalent to (formula and circle in the 1st photo) 180 + 30 = 210°.
So theta = 210° (3rd Quadrant) = 30° (1st Quadrant).

Now just transfer the cos 30° to the 3rd Quadrant and the signal will be negative (as shown in the 2nd photo attached).