中4數學(二次方程)

因為男人同個女年齡差距係年年都唔變既

所以男人同女今年既差距 = 以前既差距

今年既差距 = [(x+1)^2] - (2x+11)

以前既差距 = 5x - 4

(x+1)^2 - (2x+11) = 5x-4

x^2 + 2x +1 -2x -11 = 5x-4

x^2 - 5x -6 = 0

(x-6)(x+1) = 0

x = 6 or x = -1 (reject) 英文係寫reject 唔知中文寫咩

(reject原因:
( [(-1)+1]^2 = 0歲

男人今年的年齡
= (6+1) ^2
= 49

數就咁計既
但係我唔知點解唔合理 = ="