[ ( x * 2 + 3 ) * 4 : 5 + 6 ] + 7 - 8 = 9
[ ( x * 2 + 3 ) * 4 : 5 + 6 ] + 7 = 8 + 9
[ ( x * 2 + 3 ) * 4 : 5 + 6 ] + 7 = 17
( x * 2 + 3 ) * 4 : 5 + 6 = 17 - 7
( x * 2 + 3 ) * 4 : 5 + 6 = 10
( x * 2 + 3 ) * 4 : 5 = 10 - 6
( x * 2 + 3 ) * 4 : 5 = 4
( x * 2 + 3 ) * 4 = 5 * 4
( x * 2 + 3 ) * 4 = 20
x * 2 + 3 = 20 : 4
x * 2 + 3 = 5
x * 2 = 5 - 3
x * 2 = 2
x = 2 ÷ 2
x = 1.