Question

afla necunoscuta: [18+(a-2016):3]×3-15=2019; 5+[32-(10:a×4+12)]×7=89: 8-[6400:16-(360-a×2)×5]:20=3; [36-46:2×0)+(a×7-3×12)]:7=6

Answer 1

1 .
[18+(a-2016):3]x3-15=2019
[18+(a-2016):3]x3 = 2019 + 15
18 + (a-2016):3 = 2034 : 3
18 + (a-2016):3= 678
(a-2016):3 = 678-18
a-2016= 660 x 3
a-2016 =  1980
a = 2016 + 1980
a = 3996

2.
5 + [32-(10:ax4+12)]x7=89
[32-(10:ax4+12)]x7=89-5
32-(10:ax4+12)=84:7
32-12 = (10:ax4+12)
10:ax4+12=20
10:ax4=20-12
10:a=8:4
10:a=2
a=10:2
a=5

3.
8-[6400:16-(360-ax2)x5]:20=3
8-3=[400-(360-ax2)x5]:20
400-(360-ax2)x5=5x20
400-(360-ax2)x5=100
(360-ax2)x5=400-100
360-ax2=300:5
360-ax2=60
ax2=360-60
ax2=300
a=300:2
a=150

4.
[(36-46:2x0)+(ax7-3x12)]:7=6
36+(ax7-36)=6x7
ax7-36=42-36
ax7=6+36
a=42:7
a=6