X/3=y/-7 và y-x=-20

To solve the system of equations:

1) x/3 = y/-7

To eliminate the fractions, we can cross multiply:

7x = -3y

2) y - x = -20

Now we have a system of two equations:

7x = -3y

y - x = -20

We can solve this system using substitution or elimination method.

Let's solve it using substitution:

From equation 2), we can express y in terms of x:

y = x - 20

Now substitute this value of y in equation 1):

7x = -3(x - 20)

7x = -3x + 60

Add 3x to both sides:

10x = 60

Divide both sides by 10:

x = 6

Now substitute this value of x in equation 2) to find y:

y - 6 = -20

Add 6 to both sides:

y = -14

Therefore, the solution to the system of equations is x = 6 and y = -14.