The answer for:
20)
6x-7+6x³-4x-10x³-4-8x - 2x²= −43−22−6−11
19)
8u+6+7u+(-10) + (-5u) + 8= 10+4
Answer:

Step-by-step explanation:

Cos 300 = Cos ( 360 - 60)
= Cos 60

You could use the equation
+4+(-4)=0 if:
-you earn $4 and spend it
-buying 4 candy bars then eating them
-earning 4 points then losing them