If −15 + 3x = −7 + 5x, then 6x =?

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

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Two rectangular prisms have the same volume. the area of the base of the blue prism is 418 4 1 8 square units. the area of the base of the red prism is one-half that of the blue prism. which statement is true?