(a-1)²+▕2- b▏=0
a-1=0,2- b=0
a=1,b=2
,[(a-2 b)(a+2b)-(-a+2b)(-a+2 b)]÷(-4 b)
=[(a-2 b)(a+2b)-(a-2b)(a-2 b)]÷(-4 b)
=(a-2 b)[(a+2b)-(a-2b)]÷(-4 b)
=(a-2 b)×4b÷(-4 b)
=2b-a=2×2-1=3
(a-1)²+▕2- b▏=0
a-1=0,2- b=0
a=1,b=2
,[(a-2 b)(a+2b)-(-a+2b)(-a+2 b)]÷(-4 b)
=[(a-2 b)(a+2b)-(a-2b)(a-2 b)]÷(-4 b)
=(a-2 b)[(a+2b)-(a-2b)]÷(-4 b)
=(a-2 b)×4b÷(-4 b)
=2b-a=2×2-1=3