It looks like they're multiplied, then you can simply add the exponents,
b⁸ * b⁴ = b⁸⁺⁴ = b¹²
remember, b⁸=b*b*b*b*b*b*b*b and b⁴=b*b*b*b
so b⁸ * b⁴ = b*b*b*b*b*b*b*b * b*b*b*b = b¹²
Answer:

Step-by-step explanation:
Let v be the speed after the collision of both the cars.
Now, momentum is given by: mass × velocity, then by equating the total momentum before and after the collision of the two cars, we get

⇒
⇒
⇒
Thus, they are moving at the velocity of 
The answer is :
.0085470085
Hope This Helps!!
:)
For #11, the answer is the tall sipper thing. The formula for area in a cylinder is r squared times height. you did diameter squared, not radius squared