The sum of 3 fifteens and 4 twos will be 45 +8 = 53
It would be a lot better if you zoomed in for these since it’s nearly impossible to read.
Answer:

Step-by-step explanation:
The sum you are trying to understand is this.

Remember that in general when you have a geometric series
you have that
and that equality is true as long as
.
Therefore here we have
and 
Therefore we can use the formula and

Answer:
i think thats gonna be (1,6)
Step-by-step explanation:
The formula for density of an object is Density=

First you plug in the information you already know. 163.5=

Now you have to solve for the mass so you multiply 0.492 by 163.5

Lastly, you simplify and you will get 80.44. Hope this helped :)