Răspuns:
(80×(a÷16)×60-3980)÷4=3805
(80×1/16x×60-3980)÷4=3805
simplifică 80 si 16=> 5x×60-3980÷4=3805
30x-3980÷4=3805
300x-3980/4=3805
4(75x-995)/4=3805
simplifică 4 si 4=> 75x-995=3805
75x=3805+995
75x=4800
x=4800÷75
x=64
