3(x+2)(x+3)=60

3(x²+3x+2x+6)=60

x²+5x+6=60/3

x²+5x+6=20

x²+5x+6-20=0

x²+5x+6-20=0

x²+5x-14=0

(x+7)(x-2)=0

x+7=0 x-2=0

x=-7 x=2

comprobacion 1:                    comprobacion 2:
x²+5x+6=20                                 x²+6-5x=20
(2)²+5(2)+6=20                       (7)²+6-5(7)=20
4+10+6=20                                49+6-35=20
20=20                                           55-35=20
                                                          20=20