因为(a-1)^2-b^2=(a-1)²-b²=(a-1+b)(a-1-b),所以=(a-1+b)(a-1-b)=12=1×12=2×6=3×4,又a-1+b>a-1-b所以分情况讨论,得,a-1+b=12,a-1-b=1,解得a=15/2,b=11/2因为a,b不是自然数,所以舍去,a-1+b=6,a-1-b=2,解...