Răspuns :
(a-331+300)x2=978
a-331+300=978:2
=489
a-331=489-300
a-331=189
a=189+331
a=520
993:3=331
a-331+300=978:2
=489
a-331=489-300
a-331=189
a=189+331
a=520
993:3=331
[ a - (993 : 3) + 300 ] x 2 = 978
a - 331 + 300 = 978 : 2
a - 331 = 489 - 300
a - 331 = 189
a = 189 + 331
a = 520
Verific:
[ 520 - (993 : 3) + 300 ] x 2 = 978
= ( 520 - 331 + 300 ) x 2 =
= ( 189 + 300) x 2 =
= 489 x 2 =
= 978
a - 331 + 300 = 978 : 2
a - 331 = 489 - 300
a - 331 = 189
a = 189 + 331
a = 520
Verific:
[ 520 - (993 : 3) + 300 ] x 2 = 978
= ( 520 - 331 + 300 ) x 2 =
= ( 189 + 300) x 2 =
= 489 x 2 =
= 978