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chuyển đổi lại : (7x - 3) : 12 = 13
=> (7x - 3) = 13 * 12
=> 7x - 3 = 156
=> 7x = 159
=> x= 159/7
[(7x - 31) : 5] * 36 = 7236
=> [(7x - 31) : 5] = 7236 : 36 = 201
=> (7x - 31) : 5 = 201
=> 7x - 31 = 1005
=> 7x = 1036
=> x = 148
1 + 2 + 3 + 4 + 5 +... + 100 + x = 5350
SSH : \(\left(100-1\right):1+1=100\)
=> tổng : \(\frac{\left(1+100\right)\cdot100}{2}=5050\)
=> 5050 + x = 5350
=> x = 5350 - 5050 = 300
80 - 9(x - 4) = 35
=> 9(x - 4) = 80 - 35 = 45
=> x - 4 = 45 : 9
=> x - 4 = 5
=> x = 9
(3x - 21) : 4 + 108 = 114
=> (3x - 21) : 4 = 114 - 108 = 6
=> 3x - 21 = 24
=> 3x = 45
=> x = 15
[(6x - 72) : 2 - 84]*14 = 2814
=> [(6x - 72) : 2 - 84] = 201
=> (6x - 72) : 2 - 84 = 201
=> (6x - 72) : 2 = 285
=> 6x - 72 = 570
=> 6x = 642
=> x = 107
28x + 12x = 80
=> 40x = 80
=> x = 2
249 - 7(1 + x) = 200
=> 7(1 + x) = 49
=> 1 + x = 7
=> x = 6
20 - [(x - 5) * 7 + 4] = 2
=> [(x - 5) * 7 + 4] = 18
=> (x - 5)*7 + 4 = 18
=> (x - 5) * 7 = 14
=> x - 5 = 2
=> x = 7
\(\frac{7x-33}{12}=13\)
\(7x-33=13\cdot12\)
\(7x-33=156\)
\(7x=156+33\)
\(7x=189\)
\(x=\frac{189}{7}=27\)
\(\frac{7x-31}{5}\cdot36=7236\)
\(\frac{7x-31}{5}=\frac{7236}{36}\)
\(\frac{7x-31}{5}=201\)
\(7x-31=201\cdot5\)
\(7x-31=1005\)
\(7x=1005+31\)
\(7x=1036\)
\(x=\frac{1036}{7}=148\)
\(1+2+3+4+5+..+100+x=5350\)
\(\left(1+2+3+4+5+...+100\right)+x=5350\)
Phần 1 + 2 + 3 + 4 + 5 + ... + 100 có số số hạng là :
\(\frac{100-1}{1}+1=100\) ( số hạng )
\(\Rightarrow\frac{\left(100+1\right)\cdot100}{2}+x=5350\)
\(5050+x=5350\)
\(x=5350-5050=300\)
\(80-9\left(x-4\right)=35\)
\(9\left(x-4\right)=80-35\)
\(9\left(x-4\right)=45\)
\(x-4=\frac{45}{9}\)
\(x-4=5\)
\(x=5+4=9\)
\(\frac{3x-21}{4}+108=114\)
\(\frac{3x-21}{4}=114-108\)
\(\frac{3x-21}{4}=6\)
\(3x-21=6\cdot4\)
\(3x-21=24\)
\(3x=24+21\)
\(3x=45\)
\(x=\frac{45}{3}=15\)
\(14\left(\frac{6x-72}{2}-84\right)=2814\)
\(3x-36-84=\frac{2814}{14}\)
\(3x-120=201\)
\(3x=201+120\)
\(3x=321\)
\(x=\frac{321}{3}=107\)
\(28x+12x=80\)
\(x\left(28+12\right)=80\)
\(x\cdot40=80\)
\(x=\frac{80}{40}=2\)
\(249-7\left(1+x\right)=200\)
\(-7\left(1+x\right)=200-249\)
\(-7\left(1+x\right)=-49\)
\(1+x=\frac{-49}{-7}\)
\(1+x=7\)
\(x=7-1=6\)
\(20-7\left(x-5\right)+4=2\)
\(20-7\left(x-5\right)=2-4\)
\(20-7\left(x-5\right)=-2\)
\(-7\left(x-5\right)=-2-20\)
\(-7\left(x-5\right)=-22\)
\(x-5=\frac{-22}{-7}\)
\(x=\frac{22}{7}+5=\frac{57}{7}\)
1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 x 10 x 11 x 12 x 13 x 14 x 15 = 1.3076744e+12
úm ba la xin tích
Giải:
\(9-3\times\left(x-9\right)=6\)
\(3\times\left(x-9\right)=9-6\)
\(3\times\left(x-9\right)=3\)
\(x-9=3:3\)
\(x-9=1\)
\(x=1+9\)
\(x=10\)
\(4+6\times\left(x+1\right)=70\)
\(6\times\left(x+1\right)=70-4\)
\(6\times\left(x+1\right)=66\)
\(x+1=66:6\)
\(x+1=11\)
\(x=11-1\)
\(x=10\)
\(\dfrac{x}{13}+\dfrac{15}{26}=\dfrac{46}{52}\)
\(\dfrac{x}{13}=\dfrac{23}{26}-\dfrac{15}{26}\)
\(\dfrac{x}{13}=\dfrac{4}{13}\)
\(\Rightarrow x=4\)
\(\dfrac{11}{14}-\dfrac{3}{x}=\dfrac{5}{14}\)
\(\dfrac{3}{x}=\dfrac{11}{14}-\dfrac{5}{14}\)
\(\dfrac{3}{x}=\dfrac{3}{7}\)
\(\Rightarrow x=7\)
\(5\times\left(3+7\times x\right)=40\)
\(3+7\times x=40:5\)
\(3+7\times x=8\)
\(7\times x=8-3\)
\(7\times x=5\)
\(x=5:7\)
\(x=\dfrac{5}{7}\)
\(x\times6+12:3=120\)
\(x\times6+4=120\)
\(x\times6=120-4\)
\(x\times6=116\)
\(x=116:6\)
\(x=\dfrac{58}{3}\)
\(x\times3,7+x\times6,3=120\)
\(x\times\left(3,7+6,3\right)=120\)
\(x\times10=120\)
\(x=120:10\)
\(x=12\)
\(\left(15\times24-x\right):0,25=100:\dfrac{1}{4}\)
\(\left(360-x\right):0,25=400\)
\(360-x=400.0,25\)
\(360-x=100\)
\(x=360-100\)
\(x=260\)
\(71+65\times4=\dfrac{x+140}{x}+260\)
\(\left(x+140\right):x+260=71+260\)
\(x:x+140:x+260=331\)
\(1+140:x+260=331\)
\(140:x=331-1-260\)
\(140:x=70\)
\(x=140:70\)
\(x=2\)
\(\left(x+1\right)+\left(x+4\right)+\left(x+7\right)+...+\left(x+28\right)=155\)
\(10\times x+\left(1+4+7+...+28\right)=155\)
Số số hạng \(\left(1+4+7+...+28\right)\) :
\(\left(28-1\right):3+1=10\)
Tổng dãy \(\left(1+4+7+...+28\right)\) :
\(\left(1+28\right).10:2=145\)
\(\Rightarrow10\times x+145=155\)
\(10\times x=155-145\)
\(10\times x=10\)
\(x=10:10\)
\(x=1\)
Đều theo cách lớp 5 nha em!
1, 2x - 35 = 15
2x = 15 + 35
2x = 50
x = 50 : 2
x = 25.
2, 3x + 18 = 12
3x = 12 - 18
3x = -6
x = -6 : 3
x = -2.
3, / x - 1 / = 0
=> x \(\in\varnothing\).
4, -13 /x/ = - 26
/x/ = -26 : -13
=> \(\orbr{\begin{cases}x=2\\x=-2\end{cases}}\)
Vậy x \(\in\){ 2 ; -2}.
5,4 - ( 27 - 3 ) = x - ( 13 - 4 )
4 - 24 = x - 9
-20 = x - 9
-x = 9 + 20
-x = 29
x = -29.
6, 47 - ( x + 15 ) = 21
47 - x - 15 = 21
-x - 15 = 21 - 47
-x - 15 = -26
-x = -26 + 15
-x = - 11
x = 11.
7, -5 -( 24 - x) = - 11
-5 - 24 + x = -11
-24 + x = -11 + 5
-24 + x = -6
x = -6 + 24
x = 18.
8, 6 - /x/ = 2
/x/ = 6 - 2
\(\orbr{\begin{cases}x=3\\x=-3\end{cases}}\)
Vậy x \(\in\left\{3;-3\right\}.\)
9, 6 + /x/ = 2
/x/ = 2 - 6
=> x = -4.
2x - 35 = 15
=> 2x = 15 + 35
=> x = 50 : 2
=> x = 25
3x + 18 = 12
=> 3x = 12 - 18
=> x = ( -6 ) : 3
=> x = -2
| x - 1 | = 0
=> x - 1 = 0
=> x = 0 + 1
=> x = 1
-13 * | x | = -26
=> | x | = -26 : ( -13 )
=> | x | = 2
A) 1000000 - 107492 : 154 x 28 + 1000
= 1000000 - 19544 + 1000
= 981456
B) 8/15 + 4/7 + 14/30 + 12/21 + 5
= 15/7 + 5
= 50/7
C) 9/13 : 6/11 - 5/12 : 6/11
= 9/13 x 11/6 - 5/12 x 11/6
= (9/13 - 5/12) x 11/6
= 43/156 x 11/6
= 473/936
Bài 2
1) X x2 + X x 1/5 = 8/5
X x (2 + 1/5 ) = 8/5
X x 11/5 = 8/5
X = 8/5 x 5/11
X = 8/11
2) X : 3/8 = 4/3 : 3/6
X : 3/8 = 8/3
X = 8/3 x 3/8
X = 1
a) 1 000 000 - 107 492 : 154 x 28 + 1000
= 1 000 000 - 698 x 28 + 1000
= 1 000 000 - 19544 + 1000
= 980 456 + 1000
= 981 456
b) 8/15 + 4/7 + 14/30 + 12/21 + 5
= ( 8/15 + 14/30 ) + ( 4/7 + 12/21 ) + 5
= ( 16/30 + 14/30 ) + ( 12/21 + 12/21 ) + 5
= 30/30 + 24/21 + 5
= 1 + 24/21 + 5
= ( 1 + 5 ) + 24/21
= 6 + 24/21
= 150/21
= 50/7
\(1)\)
\(-3-18\)
\(=-(3+18)\)
\(=-21\)
\(-7\times-5\)
\(=7\times(-1)\times(-5)\)
\(=7\times5\)
\(=35\)
\(5+(-11)\)
\(=5-11\)
\(=-6\)
1,
a) -3 - 18=-21
b) (-7).(-5)=35
c) 5+(-11)=-6
2,
a) -2-13+(-14)-19=-48
b) 221 + 4[(-5).8-4]=45
c) (-2)3.(-2)2+32=0
d) -15.12 - 8.(-12)=-84
3,
a) x:(-2)=9
=>x =9.(-2)
=>x =-18
b)4x+(-8)=24
=>4x =24-(-8)
=>4x =32
=>x =32:4
=>x =8
c) (3x)(x+7)=0
\(\Rightarrow\hept{\begin{cases}3x=0\\x+7=0\end{cases}\Rightarrow\hept{\begin{cases}x=0:3\\x=0-7\end{cases}\Rightarrow}\hept{\begin{cases}x=0\\x=-7\end{cases}}}\)
a) 4 × (5 - x) = x
20 - 4x = x
x + 4x = 20
5x = 20
x = 20 : 5
x = 4
b) 1/2 (x - 14) = 2
x - 14 = 2 : 1/2
x - 14 = 4
x = 4 +14
x = 18
c) 18/13 + 3 × x = 3
3x = 3 - 18/13
3x = 21/13
x = 21/13 : 3
x = 7/13
d) đề khó hiểu