Plzzz help me with this problem

What is the expression in factored form? 225x^2 - 144 a. 9(5x+4)^2 b. 9(5x-4)^2 c. 9(4x+5)(4x-5) d. 9(5x+4)(5x-4)

Find the domain of the following expression: 1/(√x)-2

What is the radius of the cone in the diagram? round your answer to the nearest whole number