Răspuns :
1)
(a × 3 - 45) × 3 - 6 = 336
(a × 3 - 45) × 3 = 336 + 6
(a × 3 - 45) × 3 = 342
a × 3 - 45 = 342 : 3
a × 3 - 45 = 114
a × 3 = 114 + 45
a × 3 = 159
a = 159 : 3
a = 53
2)
[(a × 2 - 100) × 2 + 10] × 2 + 10 = 270
[(a × 2 - 100) × 2 + 10] × 2 = 270 - 10
[(a × 2 - 100) × 2 + 10] × 2 = 260
(a × 2 - 100) × 2 + 10 = 260 : 2
(a × 2 - 100) × 2 + 10 = 130
(a × 2 - 100) × 2 = 130 - 10
(a × 2 - 100) × 2 = 120
a × 2 - 100 = 120: 2
a × 2 - 100 = 60
a × 2 = 60 + 100
a × 2 = 160
a = 160 : 2
a = 80
(a × 3 - 45) × 3 - 6 = 336
(a × 3 - 45) × 3 = 336 + 6
(a × 3 - 45) × 3 = 342
a × 3 - 45 = 342 : 3
a × 3 - 45 = 114
a × 3 = 114 + 45
a × 3 = 159
a = 159 : 3
a = 53
2)
[(a × 2 - 100) × 2 + 10] × 2 + 10 = 270
[(a × 2 - 100) × 2 + 10] × 2 = 270 - 10
[(a × 2 - 100) × 2 + 10] × 2 = 260
(a × 2 - 100) × 2 + 10 = 260 : 2
(a × 2 - 100) × 2 + 10 = 130
(a × 2 - 100) × 2 = 130 - 10
(a × 2 - 100) × 2 = 120
a × 2 - 100 = 120: 2
a × 2 - 100 = 60
a × 2 = 60 + 100
a × 2 = 160
a = 160 : 2
a = 80
53 x 3 = 159
159 - 45 = 114
114 x 3 = 342
342 - 6 = 336
Calculul se face invers
336 + 6 = 342 : 3 = 114 + 45 = 159 : 3 = 53
159 - 45 = 114
114 x 3 = 342
342 - 6 = 336
Calculul se face invers
336 + 6 = 342 : 3 = 114 + 45 = 159 : 3 = 53