The solution to the system of equations:

1/2, 5/2

Step-by-step explanation:

Rearrange the system of equations.

-3x + y = -1

x + y = 3

Multiply the bottom equation by 3

3x + 3y = 9

Now add the two equations

4y = 10

y = 5/2

Now plug y back in to solve for x in one equation

x + y = 3

x + 5/2 = 3

x = 1/2

Answer in coordinates: 1/2, 5/2

300m

Step-by-step explanation:

20 x 15 = 300