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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 6: Tìm số nguyên x thỏa mãn: a) [230-(15-5x).3=390. b) 345-5ᕽ⁻³=14ᒾ+24 c) x-[24+(-28)]=-8. d) 720:[41-(2x-45)]=2².5 Gi

Toán Lớp 6: Tìm số nguyên x thỏa mãn:
a) [230-(15-5x).3=390. b) 345-5ᕽ⁻³=14ᒾ+24
c) x-[24+(-28)]=-8. d) 720:[41-(2x-45)]=2².5
Giải giúp em với ạ

Comments ( 1 )

  1. $ a) 230 – ( 15 – 5x ) = 390 : 3 = 130 $ 
    $ 15 – 5x = 230 – 130 = 100 $ 
    $ x = ( 15 – 100 ) : 5 = ( -85 ) : 5 = -17 $ 
    $ b) 345 – 5^{x-3}=14^2+24=196+24=220 $
    $ 5^{x-3}=345-220=125 ⇒ x-3=3 ⇒ x=3+3=6 $
    $ c) x – [ 24 + ( -28 ) ] = -8 $ 
    $ x – ( -4 ) = -8 ⇒ x + 4 = -8  ⇒ x = -8 – 4 = -12 $
    $ d) 41 – ( 2x – 45 ) =  720 : ( 2^2 . 5 ) =720 : ( 4.5)=720:20=36 $ 
    $ 2x – 45 = 41-36=5 $ 
    $ x=(5+45):2=50:2=25 $ 

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222-9+11+12:2*14+14 = ? ( )