If you know the coordinates of two points

of two points, the slope of the line passing through them is given by

So, if we choose in this example

The slope is

I'm pretty sure x=0.85. Good luck!
That variable from the number of black marble divide by all marble.
5/4+7+5 = 0.3125
Answer: 2
This question is asking you to divide 20 by 10. This means:
20 ÷ 10=2
If 10 can go into a number 2 times, it means that 10•2=20. So, since we dont know how many times 10 goes into 20, we divide 20 by 10.
Below I have attached an image of the long division in case you need to do that as well.
Hope this helps comment below for more questions :)
I think a straight edge will be best for you to use