Tolong jawab yg pinter matematika pakai cara

x/(x + 4) = (12 - 9)/(14 - 9)
x/(x + 4) = 3/5
Kalikan silang
5x = 3x + 12
5x - 3x = 12
2x = 12
x = 6 ✔

EF = (AE x BC)+(BE x AD)/AE+BE
12 = (X x 14)+(4 x 9)/X+4
12 = 14X + 36/X+4
12(X+4) = 14X + 36
12X + 48 = 14X + 36
48-36 = 14X-12X
12 = 2X
12/2 = X
6 = X
Jadi, nilai X adalah 6

*semoga membantu. sukses selalu ^_^