Find the area of a room that has a width of (x+3) and a length of (2x-5).?

(x + 3) X (2x - 5)
(2x to the power of 2 - 5x) + (6x - 15) = 0
2x to the power of 2 + x - 15 = 0
2x to the power of 2 + x = 15
x = 15 - 2x to the power of 2

(2x - 5)(x + 3)
= 2x*x - 5*x + 2x*3 - 5*3 (* = multiply)
= 2x^2 - 5x + 6x - 15
= (2x^2 + x - 15) square units

area of rectangle = length* breadth. You forgot it.
So answer is (x+3)(2x-5) = 2(x^2) +x - 15.