PANJANG AB ADALAH... Mohon pake cara yg lengkap ya

MAPEL = MATEMATIKA
KELAS = 9
BAB = BANGUN DATAR

diketahui =
DC = 6cm
EF = 8cm
BF = 3cm
CF = 2cm

ditanya = AB ??

[tex]ef = \frac{(cf + \times ab) + (bf \times dc)}{bf + cf} \\ \: \: 8 = \frac{(2 \times ab) + (3 \times 6) }{3 + 2} \\ \: \: 8 = \frac{2ab + 18}{5} \\ 8 \times 5 = 2ab + 18 \\ \: \: \: \: \: \: 40 = x2ab + 18 \\ 40 - 18 = 2ab \\ \: \: \: \: \: \: \: \: \: \: 22 = 2ab \\ \: \: \: \: \: \: \: \: \: \: ab = \frac{22}{2} \\ \: \: \: \: \: \: \: \: \: \: ab = 11[/tex]

opsi A. 11cm
semoga membantu

jawab

EF = (DC . FB ) + (AB . FC) / (BC)
8 = (6x 3) + (ABx2) / (5)

5(8) = 18 + 2 AB
2AB  = 40- 18 = 22
AB = 11