Răspuns:
X = 15
Explicație pas cu pas:
( 3 x X - 5 ) : 4 +( 275 - 2 x30) : 5 = 53
( 3 x X - 5 ) : 4 + (275- 60) :5 = 53
(3 x X - 5) :4+ 215 : 5 = 53
( 3 x X - 5 ) : 4 + 43 = 53
( 3 x X -5 ) : 4 = 53 - 43
( 3 x X - 5) : 4 = 10
(3 x X - 5) = 10 x 4
( 3 x X - 5 ) = 40
3 x X = 40 + 5
3 x X = 45
X = 45 : 3
X= 15
