Area of the land: (x + 35) * (x + 35) = (x + 35)^2

Area of the tank: x * x = x^2

Remaining area of the land: (Area of the land) - (Area of the tank) = 2275 => (x + 35)^2 - x^2 = 2275

2. Solve the equation

Expand (x + 35)^2: x^2 + 70x + 1225 - x^2 = 2275
Simplify: 70x + 1225 = 2275
Isolate x: 70x = 2275 - 1225
Solve for x: 70x = 1050 => x = 1050 / 70 => x = 15

3. Calculate the area of the tank

Area of the tank = x * x = 15 * 15 = 225 square meters