[432-(ax3-791)-692+2]:316=4
[ 432 - ( a×3 - 791) - 692+2] = 4 × 316
432 - ( a×3 - 791) - 692+2 = 1 264
- ( a×3 - 791) -692+2 = 1 264 -432
- (a ×3 -791) -692 +2 = 832
-a ×3 + 791 = 832+ 692-2
- a × 3 - 791 = 1 522
- a × 3 = 1 522 + 791
- a × 3 = 2 313
- a = 2 313 : 3
a = - 771
