question is in the pic.Thank you

The accompanying figure shows a rectangle inscribed in an isosceles right triangle whose hypotenuse is 30 units long. a. Express the y-coordinate of P in terms of x. (You might start by writing an equation for the line AB.) b. Express the area of the rectangle in terms of x. P(x,?) A -15 X a. The expression for the y-coordinate of P is (Type an expression using x as the variable.) b. The expression for the area of the rectangle is|]. (Type an expression using x as the variable.)