Question

(2x+3)(3-r)-(2x-5)(3-r)

Answer 1

usas distributiva

(2x+3)(3-r)-(2x-5)(3-r)
(6x-2xr+9-3r)  - (6x-2xr-15+5r)
6x-2xr+9-3r-6x+2xr+15-5r
24-8r (ya que lo subrayado se simplifica)    =D

Answer 2

(2x+3)(3-r) - (2x-5)(3-r)          podemos sacar factor comun (3 -r)
(3- r)(2x + 3 -2x + 5)
(3 - r) ( 3 + 5)
( 3 -r) (8)
24 - 8r

Espero que te sirva, salu2!!!!