Try this option:
if x+y=-9 is I (one)
and x+2y=-25 is II (two), then
if II-I, then (x+2y)-(x+y)=-25+9 ⇔ y=-16.
Answer:
=
units
Step-by-step explanation:
x₁ = 2 ; y₁ = 5
x₂ = 6 ; y₂ = -1
D = 
=
=
= 
D =
units
Answer:

Step-by-step explanation:

Subtract 57 from both sides:

Divide both sides by 4:

So you can you the Pythagorean theorem to solve this problem.
if each side of the square is a certain length x, then the square is made up of two right triangles.
the sides adjacent to the right angle are length x while the hypoteneus is the diagonal whcih measures 36 feet.
a^2 + b^2 = c^2
x^2 + x^2 = 36^2
2x^2 = 1296
x^2 = 648
x = 25.456
area of a square = x^2 = 648 ft^2