Help me friends.. i cant do it..

4) misal
10 m = 25 cm
x = 8 cm
maka
1.000 cm = 25 cm
x = 8 cm
jadi
x = ( 1.000 × 8 ) ÷ 25
x = 320 cm ( A )

5) 176 km = 11 liter
( 176 + 40 ) km = x liter
maka
x ={ ( 176 + 40 ) × 11 } ÷ 176
x = ( 216 × 11 ) ÷ 176
x = 2376 ÷ 176
x = 13,5 liter ( D )

6) 2^4x-3 = 8^x-7
2^4x-3 = (2³)^x-7
=> 4x - 3 = 3 ( x - 7 )
=> 4x - 3 = 3x - 21
=> 4x - 3x = 3 - 21
=> x = - 18 ( A )

8) 2 minggu = 2 × 7 = 14 hari
total pekerjaan = 15 × 14 = 210
total pekerja jika ingin selesai 10 hari
= 210 ÷ 10
= 21 orang ( B )

9) √125 - √5 + √3125
= √( 5×25) - √5 + √(5×625)
= 5√5 - √5 + 25√5
= 29√5 ( D )