If 4 is added to 8 to equal 12, how would the operation be undone​

Find the center and the radius of the circle with the equation: x^2-2x+y^2+4y+1=0?

Jane moves from a house with 71 square feet of closet space to an apartment with 45.44 square feet of closet space. what is the percentage decrease of jane’s closet space?

The rectangle shown has a perimeter of 108 cm and the given area. its length is 6 more than five times its width. write and solve a system of equations to find the dimensions of the rectangle.