- ?- U" [! @9 M# Q請問:爸爸現在在哪裡?& `3 {5 V- N$ F7 C' {7 q6 Z
$ Z. }' [2 g& m. }" F: t
Sol: assume Age of Mother = x 8 ~9 J. C+ r$ i6 g Age of Children = y1 x$ T& C5 `; ^4 D- C
. i- p8 U- x! w; D x-y =21 (1)% ~8 `1 A( z; ~" t: p
(x+6)=5(y+6) (2) 3 K8 }: r V x: C& y6 r3 K 7 U7 P$ M6 x) u 代入 x= 21+y 到 (2) Z: ^/ m" w4 b2 a# i, ~2 o& {/ o; Z' J. ~" |
27+y = 5y+30 4y= -3( T0 A% B. p0 E" Y- R4 f( D
y= - 3/4 代表爸爸現在跟媽媽在一起~