18. 4 + 56 + 11. 4 + 128 25. 78. 40 + 4. 87. 2. 125 21.(x + 1) = 21 (3.x) : 48 = 42 : 23 (16x – 126).8 = (312 : 26)2 x2.(5 – x) = 0 (12.x + 11).23 = 529 GIÚP MÌNH NHA MG
2 câu trả lời
`18 . 4 + 56 + 11 . 4 + 128`
`= (18 + 11) . 4 + 56 + 128`
`= 29 . 4 + 184`
`= 116 + 184`
`= 300`
`25 . 78 . 40 + 4 . 87 . 2 . 125`
`= 1000 . 78 + 1000 . 87`
`= 1000 . (78 + 87)`
`= 1000 . 165`
`= 165000`
`21 . (x + 1) = 21`
`=> x + 1 = 1`
`=> x = 0`
`(3 . x) : 48 = 4^2 : 2^3`
`=> (3 . x) : 48 = 2`
`=> 3 . x = 96`
`=> x = 32`
`(16x - 126) . 8 = (312 : 26)^2`
`=> (16x - 126) . 8 = 12^2`
`=> (16x - 126) . 8 = 144`
`=> 16x - 126 = 18`
`=> 16x = 144`
`=> x = 9`
`x^2 . (5 - x) = 0`
`=> x^2 = 0` hoặc `5 - x = 0`
`=> x = 0` hoặc `x = 5`
`(12x + 11) . 23 = 529`
`=> 12x + 11 = 23`
`=> 12x = 12`
`=> x = 1`
$a)18. 4 + 56 + 11. 4 + 128
= 4.(18+11)+56+128
=4.29+56+128
= 116+56+128
=300
b)25. 78. 40 + 4. 87. 2. 125
=1000.78+ 1000.87
=78000+87000
=165000
c) 21.(x + 1) = 21
x+1=21:21
x+1=1
x=0
d) (3.x) : 48 = 42 : 23
3.x=42:23.48
3.x= $$\frac{2016}{23}
x=$ $\frac{2016}{23} : 3
x=$ $\frac{672}{23}
e) (16x – 126).8 = (312 : 26)2
(16x-126).8=24
16x-126=24.8
16x-126=192
16x=192+126
16x=318
x=19,875
f) x2.(5 – x) = 0
=>x.2=0 hoặc 5-x=0
=>x=0 hoặc x=5
g)(12.x + 11).23 = 529
12.x+11=529:23
12.x+11=23
12.x=12
x=1$
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