Respuesta :

magic and experience and trial and error
use ac method
2 times 3=6
what 2 numbers multiply to get 6 and add to get 5?, 2 and 3
split the middle number into those

2r²+2r+3r+3
group
(2r²+2r)+(3r+3)
factor
2r(r+1)+3(r+1)
undistribute
(r+1)(2r+3)