You can reword the two equations as:
-5x-y=15 (Divide original value by 3)
-2x+6y=6
Then use elimination to find x:
-30x-6y=90 (Multiply by 6 to get y values to be same to cancel out)
-2x+6y=6
You're left with:
-32x=96. Which can then be solved to find x which is -3.
Then plug back in
-2x+6y=6
Now to: -2(-3)+6y=6.
Which reduces to 6+6y=6. So y=0.
To graph them, just reword the equations (yes once again) so that y is in front.
y=-5x-15 and y=(1/3)x+1
Answer:

Step-by-step explanation
The standard equation of a circle centered at origin is 
r = radius of the circle
The circle is passing through the point (0,5)
∴ radius 



∴ The equation of the circle is

Answer:
x = 8.5
Step-by-step explanation:
I got this answer by assuming the triangles were congurent, if they are not, the answer may vary.
first, make an equation:
x + 8 = 3x - 9
bring 3x to the other side, by subtracting it
-2x + 8 = -9
Subtract 8
-2x = -17
divide by -2
x = 8.5
Then, just sub x into the formulas
Answer:
2:5
Step-by-step explanation:
Since there are 2 nickles and 5 quarters there are 2 nickles for every 5 quarters so answer is 2:5
Answer:
16.66months
Step-by-step explanation:
2500/150