Simple interest: please help me

Given that abcd is a rhombus, what is the value of x?

How is the equation of this circle written in standard form? x2 + y2 - 6x + 14y = 142 a) (x - 3)2 + (y + 7)2 = 200 b) (x+ 3)2 + (y - 7)2 = 200 (x - 6)2 + (y + 14)2 = 142 d) (x+6)2 + (y- 14)2 = 142

Which radical expression is a rational number? a. √ 360 b. √ 644 c. √ 225 d. √ 122