Foil:
First term
Outer term
Inner term
Last term
By using foil we just times the first terms together so: x*x=x^2
Then we times the outer terms together so: x*9=9x
Then we times the inner terms together so:7*x=7x
Finally we times the last terms together so: 7*9=63
So our equation is:
X^2+9x+7x+63
Now we collect the like terms
Answer: x^2+16x+63
Hope this helped
2.50x=90
X stands for the number of times he can ride the bus.
To solve this, you'd take 90/2.5 which is equivalent to 36. He would be able to ride the bus 36 times.
Answer:
C. Slope and 
Step-by-step explanation:
We're missing the graph itself, but I can make an educated guess:
- Assuming x = volume and y = mass:

density = mass/volume
x = volume = run
y = mass = rise
mass/volume = rise/run = slope
The slope of the line (assuming the graph is purely linear) represents mass/volume, which is the formula for density.
I had to Google the density of silver itself. Do the math from the graph for a more appropriate answer, as the graph may be less scientifically precise.
The answer should be 16√5