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[(x+34)-50].2=56
`<=>(x+34-50).2=56
`<=>(x-16).2=56
`<=>2x-32=56
`<=>2x=56+32
`<=>2x=88
Ta có: \(\left(x+34-50\right)\cdot2=56\)
\(\Leftrightarrow x-16=28\)
hay x=44
a, 15 : x + 120 : 12 =15
\(\Rightarrow\) 15 : x + 10 = 15
\(\Rightarrow\) 15 : x = 15 - 10
\(\Rightarrow\) 15 : x = 5
\(\Rightarrow\) x = 15 : 5
\(\Rightarrow\) x = 3
b, [ ( x + 34 ) - 50].2 = 56
\([\left(x+34\right)-50]=56:2\)
(x + 34 ) - 50 = 28
x + 34 = 28+50
x+34 =78
x = 78 - 34
x = 44
a,15:x+120 : 12 = 15
15 : x + 10 = 15
15: x = 15 -10
15 : x = 5
x = 15 : 5
x = 3
vậy x = 3
a, 91 - 5 . ( 5 + x ) = 61
5 . (5+x)=91-61
5 . (5+x)=30
5+x=30:5
5+x=6
x=6-5
x=1
Bài 1. Tìm số tự nhiên x biết:
a, 91 - 5 . ( 5 + x ) = 61
5(5 + x) = 91 - 61
5(5 + x) = 30
5 + x = 30 : 5
5 + x = 6
x = 6-5
x= 1
b, ( x+ 34 ) - 50 = 56 : 2
( x + 34 ) - 50 = 28
x + 34 = 28 + 50
x + 34 = 68
x= 78 - 34
x = 44
Tk mk nha
a,91-5(5+x)=61
=>25+5x=91-61=30
=>5x=30-25=5
=>x=1
b,\([\left(x+34\right)-50]\)x2=56
=>(x+34)-50=56:2=28
=>x+34=28+50=78
=>x=78-34=44.
c,1045-\([2015-\left(3x-24\right)]\)=5
=>2015-(3x-24)=1045-5=1040
=>3x-24=2015-1040=975
=>3x=975+24=999
=>x=999:3=333
d,\([195-\left(3x-27\right)]\)x39=4212
=>195-(3x-27)=4212:39=108
=>3x-27=195-108=87
=>3x=87+27=117
=>x=39
e,30-3(x-2)=18
=>30-3x+6=18
=>30-3x=18-6=12
=>3x=30-12=18
=>x=18:3=6
a) \(...\Rightarrow5\left(5+x\right)=91-61=30\)
\(\Rightarrow\left(5+x\right)=30:5=6\Rightarrow x=6-5=1\)
b) \(...\Rightarrow\left(x+34\right)-50=56:2=28\)
\(\Rightarrow\left(x+34\right)=28+50=78\Rightarrow x=78-34=44\)
c) \(...\Rightarrow2015-\left(3x-24\right)=1045-5=1040\)
\(\Rightarrow\left(3x-24\right)=2015-1040=975\)
\(\Rightarrow3x=975+24=999\Rightarrow x=999:3=333\)
d) \(...\Rightarrow195-\left(3x-27\right)=4212:39=108\)
\(\Rightarrow\left(3x-27\right)=195-108=87\)
\(\Rightarrow3x=87+27=114\Rightarrow x=114:3=38\)
e) \(...\Rightarrow3\left(x-2\right)=30-18=12\Rightarrow x-2=12:3=4\)
\(\Rightarrow x=4+2=6\)
1; - (-66) + 34 + (-73) - 27 + 99
= 66 + 34 - 73 - 27 + 99
= (66 + 34) - (73 + 27) + 99
= 100 - 100 + 99
= 0 + 99
= 99
2; 54 - (45 - 30 + 54) - 30 + 5
= 54 - 45 + 30 - 54 - 30 + 5
= (54 - 54) + (30 - 30) - (45 - 5)
= 0 + 0 - 40
= - 40
a) 19 + (x - 23) = 50
x - 23 = 50 - 19
x - 23 = 31
=> x = 31 + 23
x = 54
b) (273 - x) - 140 = 34
(273 - x) = 34 + 140
(273 - x) = 174
x = 273 - 174
x = 99
c) 56 - (x - 14) = 22
x - 14 = 56 - 22
x - 14 = 34
x = 34 + 14
x = 48
d) 172 - (137 - x) = 93
137 - x = 172 - 93
137 - x = 79
x = 137 - 79
x = 58
e) 13. (x - 14) = 91
x - 14 = 91 : 13
x - 14 = 7
x = 14 + 7
x = 21
g) (13 - x).17 = 51
13 - x = 51 : 17
13 - x = 3
x = 13 - 3
x = 10
chúc bn học giỏi ^^ !
ok mk nha!! ! 5654645645767676576558578779769675634636457567687689978978978978766876765657886567567
1.19+(x-23)=50
<=>x-23=50-19
<=>x-23=31
<=>x=31+23
<=.x=54
vậy x=54
a) 91 - 5(5+x) = 61
5(5+x) = 30
5+x=6
x=1
b) [(x+34) - 50]2 = 56
(x+34) - 50 = 28
x+34 = 78
x= 44
Tập hợp con của A có 2 phần tử:
{1;2} {1;3} {1;4}
(2;3} {2;4}
{3;4}
a) 91 - 5 . ( 5 + x ) = 61
5 . ( 5 + x ) = 61
5 . ( 5 + x ) = 30
5 + x = 30 : 5
5 + x = 6
x = 6 - 5
x = 1.
b) [ ( x + 34 ) - 50 ] . 2 = 56
[ ( x + 34 ) - 50 ] = 56 : 2
[ ( x + 34 ) - 50 ] = 28
x + 34 = 28 + 50
x + 34 = 78
x = 78 - 34
x = 44.
2.Cho tập hợp A = { 1 ; 2 ; 3 ; 4 }
B = { 1 ; 2 }
C = { 1 ; 3 )
D = { 1 ; 4 }
E = { 2 ; 3 }
F = { 2 ; 4 }
\(\text{1.-(-66)+34+(-73)-27+99}.\)
\(=66+34-73-27+99=100-100+99=-99.\)
\(\text{2.54-(45-30+54)-30+5}.\)
\(54-45+30-54-30+5=\left(54-54\right)+\left(-45+5\right)+\left(30-30\right)=-40.\)
\(\text{3.42-56+33-(33-56+42)}.\)
\(=42-56+33-33+56-42=\left(42-42\right)+\left(-56+56\right)+\left(33-33\right)=0.\)
\(\text{4.50-(47+50-18)+(47-18)}.\)
\(=50-47-50+18+47-18=\left(50-50\right)+\left(-47+47\right)+\left(18-18\right)=0.\)
\(\text{5.10-(28-30+4)}.\)
\(=10-28+30-4=10+30-20-8-4=20-12=8.\)
\(\text{6.-(-73)+(44-94+27)+94}.\)
\(=73+44-94+27+94=\left(73+27\right)+\left(-94+94\right)+44=100+44=144.\)
1: =66+34-73-27+99=99
2: =54-45+30-54-30+5=-40
3: =42-56+33-33+56-42=0
4: =50-47-50+18+47-18=0
5: =10-28+30-4=2-4+10=12-4=8
Ta có: \(\left(x+34-50\right)\cdot2=56\)
\(\Leftrightarrow x-16=28\)
hay x=44
[(x+34) -50] .2 = 56
(x+34) -50 = 56 : 2
(x+34) -50 = 28
x+34 = 28 + 50
x+34 = 78
x = 18 - 34
\(\Rightarrow x=...\)