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Cần gấp bài 1 cảm ơn Cần gấpppppppppp
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Helga
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a) 24 – x : 5 = 3
=>x : 5 = 24 – 3
=>x : 5 = 21
=>x = 21 . 5
=>x = 105
b) 36 – 6 . (x + 4) = 12
=>6 . (x + 4) = 36 – 12
=>6 . (x + 4)=24
=>x + 4=24 : 6
=>x + 4 = 4
=>x = 4 – 4
=>x = 0
c) 40 – (2x – 18) : 3= 28
=>(2x – 18) : 3 = 40 – 28
=>(2x – 18) : 3 = 12
=>(2x – 18) = 12 . 3
=>(2x – 18) = 36
=>2x = 36 + 18
=>2x = 54
=>x = 54 : 2
=>x= 27
d) (2x – 1) : 3 = 2^4 + 3^2
=>2x – 1 : 3 = 16 + 9
=>(2x – 1) : 3=25
=>2x – 1 = 25 . 3
=>2x – 1 = 75
=>2x = 75 + 1
=>2x =76
=>x = 76 ÷ 2
=>x = 38
g) (x – 4) . (x + 5)= 0
=>x – 4 . x + 5 = 0
=>x . (-4 + 5) = 0
=>x . (-1) = 0
=>x = 0 : (-1)
=>x = 0
Đáp án:
Giải thích các bước giải: a. 24-x:5=3
x:5=24-3
x:5=21
x=21×5
x=105
b. 36-6×(x+4)=12
6×(x+4)=36-12
6×(x+4)=24
x+4=24÷6
x+4=4
x=4-4
x=0
f. (x-4)×(x-5)=0
⇒x-4=0(1) hoặc x+5=0(2)
giải 1 ; x-4=0⇒x=0+4⇒x=4
giải 2 ; x+5=0⇒x=0-5⇒x=-5
Vậy x∈( 4 ; -5)
c. 40-(2x-18)÷3=28
(2x-18)÷3=40-28
(2x-18)÷3=12
(2x-18)=12×3
(2x-18)=36
2x=36+18
2x=54
x=54÷2
x=27
d.(2x-1)÷3=2^4+3²
(2x-1)÷3=16+9
(2x-1)÷3=25
(2x-1)=25×3
(2x-1)=75
2x=75+1
2x=76
x=76÷2
x=38