Given :
Two equations :
-8x + 3y = -17 ....1)
3x - y = 7 ....2)
To Find :
The solution of the system.
Solution :
Multiplying equation 2) by 3 and adding with equation 1), we get :
(-8x + 3y) + 3(3x - y) = -17 + 21
x = 4
Putting above value of x equation 2) we get :
12 - y = 7
y = 5
Therefore, solution of system is ( 4,5 ).
The answer would be 73 degrees because 62 +12 = 73

The square root of 729 is in fact 27, as it is a perfect square, but this is not well known, so we can figure it out like this:
What goes into 729 that are perfect squares? 81 and 9:

Take the square root of 81 (9) and the square root of 9 (3). Move these to the outside of the square root (they will multiply with 3 since 3 is multiplied to the square root in the original problem)

Now, just multiply:
If I am reading this correctly...the ratio would be
Austalia championships: the total of countries championships
for example australia = 18 and the other countries have 300
ratio would be 18:300 or 18/300
Then simplify 3:50 or 3/50
Hope this was helpful!