172x2 - 79 : 983 = 2-3
<=> 172x2 - 79 : ( 2 . 72 )3 = 1/8
<=> 172x2 - 79 : ( 23 . 76 ) = 1/8
<=> 172x2 - 79 : 23 : 76 = 1/8
<=> 172x2 - 73 : 23 = 1/8
<=> 172x2 - ( 7 : 2 )3 = 1/8
<=> 172x2 - 343/8 = 1/8
<=> 172x2 = 43
<=> x2 = 43/172 = 1/4
<=> x = ±1/2