一國中數學問題(很急)

Question

若定義算式A*B=(A+1)(2B-1)-3 則(X*X)*1=-3的X解為何?

抱歉更正

A@B=(A 1)(2B-1)-3 則(X@X)@1=-3的X解為何?

A@B=(A 1)(2B-1)-3 則(X@X)@1=-3的X解為何?

Answer 1

(X*X)*1 = -3
=> [(X+1)(2X-1)-3]*1 = -3
=> {[(X+1)(2X-1)-3]+1}{2*1 -1} - 3 = -3
=> (2X2+X-1 -3 +1)(1) = 0
=> 2X2+X-3 = 0
=> (X-1)(2X+3) = 0
=> X = 1 或 -3/2
如果有問題, 請來函討論. 不然, 我可能會錯失你再補充的疑點.

Answer 2

(x*x)=-3
(2x-1)(x+1)-3=-3
2x平方+x-4=-3
2x平方+x-1=0
平方差公式得 (2x-1)(x+1)=0
所以x = 1/2 or -1