Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(a,70-5\times\left(x-3\right)=45\)
\(5\times\left(x-3\right)=70-45\)
\(5\times\left(x-3\right)=25\)
\(x-3=25:5\)
x - 3 = 5
x = 5 + 3 = 8
vậy x = 8
\(b,12+\left(5+x\right)=20\)
12 + 5 + x = 20
17 + x = 20
x = 20 - 17 = 3
vậy x = 3
c, 130 - (100 + x) = 25
130 - 100 - x = 25
30 - x = 25
x = 30 - 25 = 5
vậy x = 5
\(g,10+2\times x=4^5:4^3\)
\(10+2\times x=4^2\)
\(10+2\times x=16\)
\(2\times x=16-10\)
\(2\times x=6\)
x = 6 : 2 = 3
vậy x = 3
h, \(14\times x+54=82\)
\(14\times x=82-54\)
\(14\times x=28\)
\(x=28:14=2\)
vậy x = 2
\(k,15\times x-133=17\)
\(15\times x=17+133\)
\(15\times x=150\)
\(x=150:15=10\)
vậy x = 10
Bài 1:
6) 3x + 2³ = 17 + 3²
3x + 8 = 17 + 9
3x + 8 = 26
3x = 26 - 8
3x = 18
x = 18 : 3
x = 6
Vậy x = 6
Bài 2:
3) 145 - (125 + x) = 12
125 + x = 145 - 12
125 + x = 133
x = 133 - 125
x = 8
Vậy x = 8
6) 3³ - (x - 5) = 2²
27 - (x - 5) = 4
x - 5 = 27 - 4
x - 5 = 23
x = 23 + 5
x = 28
Vậy x = 28
9) (x + 7) - 15⁰ = 202 - 19
(x + 7) - 1 = 189
x + 7 = 189 + 1
x + 7 = 190
x = 190 - 7
x - 183
Vậy x = 183
a ) x +5 = -10
x = -10 -5
x = - 15
b) x - ( - 10 ) = 5
x = 5+(-10)
x = -5
c) \(\left|x\right|\) -5 = 3
\(\left|x\right|=8\)
x ϵ { -8 ; 8 }
d) 15 - ( - x ) = 20
Không có số tự nhiên x nào mà 15 ( - x ) = 20
e ) \(\left|x-4\right|=3-\left(-7\right)\\ \left|x-4\right|=10\\ \left|x\right|=14\\ x\in\left\{\pm14\right\}\)
f ) \(\left|x+5\right|=10-\left(-20\right)\\ \left|x+5\right|=30\\ \left|x\right|=25\\ x\in\left\{\pm25\right\}\)
a) \(\left(x-1\right):3=2^3\) \(\Leftrightarrow\) \(\left(x-1\right):3=8\) \(x+1=24\) \(\Leftrightarrow\) \(x=23\) vậy \(x=23\)
b) \(12-2\left(x+5\right)=-10\) \(\Leftrightarrow\) \(12-2x-10=-10\)
\(\Leftrightarrow\) \(-2x=-12\) \(\Leftrightarrow\) \(x=6\) vậy \(x=6\)
c) \(x-12\left(x+5\right)=-10\) \(\Leftrightarrow\) \(x-12x-60=-10\)
\(\Leftrightarrow\) \(-11x=50\) \(\Leftrightarrow\) \(x=\dfrac{50}{-11}\) vậy \(x=\dfrac{50}{-11}\)
e) \(13-x:2=10\Leftrightarrow-x:2=-3\Leftrightarrow x=\dfrac{3}{2}\)
f) \(\left|12-x\right|-7=5\)
th1 : \(x\le12\) thì \(\left|12-x\right|-7=5\) \(\Leftrightarrow\) \(12-x-7=5\) \(\Leftrightarrow\) \(-x=0\Leftrightarrow x=0\)
th2 : \(x>12\) thì \(\left|12-x\right|-7=5\) \(\Leftrightarrow\) \(x-12-7=5\) \(\Leftrightarrow\) \(x=24\) vậy \(x=0;x=24\)
i) \(x^2-7=2\Leftrightarrow x^2=9\Leftrightarrow x=3\) vậy \(x=3\)
k) \(x^3-4=-12\) \(\Leftrightarrow\) \(x^3=-8\) \(\Leftrightarrow x=-2\) vậy \(x=-2\)
a)\(\left(x-1\right):3=2^3\Rightarrow x-1=2^3.3=24\Rightarrow x=25\)
b)\(12-2\left(x+5\right)=-10\Leftrightarrow12-2x-10=-10\Rightarrow2-2x=-10\Rightarrow2x=12\Rightarrow x=6\)c)\(x-12\left(x+5\right)=-10\Rightarrow x-12x-60=-10\Rightarrow-11x-60=-10\Rightarrow-11x=-70\Rightarrow x=\dfrac{70}{-11}\)d)\(6-\left|x\right|=5\Rightarrow\left|x\right|=1\Rightarrow x=\left\{\pm1\right\}\)
Làm nốt nha
a, \(2^x-15=17\)
\(\Rightarrow2^x=17+15\)
\(\Rightarrow2^x=32\)
\(\Rightarrow2^x=2^5\)
\(\Rightarrow x=5\)
b, \(\left(7x-11\right)^3=2^5.5^2+200\)
\(\Rightarrow\left(7x-11\right)^3=32.25+200\)
\(\Rightarrow\left(7x-11\right)^3=1000\)
\(\Rightarrow\left(7x-11\right)^3=10^3\)
\(\Rightarrow7x-11=10\)
\(\Rightarrow7x=10+11\)
\(\Rightarrow7x=21\)
\(\Rightarrow x=21:7\)
\(\Rightarrow x=3\)
c, \(x^{10}=1^x\)
\(\Rightarrow x\in\left\{1;0\right\}\)
\(2^x-15=17\)
\(\Rightarrow2^x=17+15\)
\(\Rightarrow2^x=32=2^4\)
\(\Rightarrow x=4\)
\(\left(7x-11\right)^3=2^5.5^2+200\)
Phần này mk ko bt làm đâu
\(x^{10}=1^x\)
\(\Rightarrow\)\(x^{10}=1\)
\(\Rightarrow x=1\)
1. Tính nhanh:
a) -37 + 54 + (-70) + (-163) + 246
= (-70) + {[(-163) + (-37)] + (246 + 54)}
= (-70) + [(-200) + 300]
= (-70) + 100
= 30
b) 24 - (-136) - (-70) + 15 - (-115)
= 24 + 136 + 70 + 15 + 115
= [70 + (15 + 115)] + (24 + 136)
= 70 + 130 + 160
= 200 + 160
= 360
2. Tính giá trị của các biểu thức sau bằng cách hợp lí nhất:
a) 136 . (- 47) + 36 . 47
= -136 . 47 + 36 . 47
= 47(-136 + 36)
= 47 . (-100)
= -4700
b) (- 48) . 72 + 36 . (- 304 )
= (- 48) . 72 + 72 . (-152)
= 72(-48 - 152)
= 72 . (-200)
= -14400
14. Tính tổng các số nguyên x biết:
a) - 2017 ≤ x ≤ 2018
x ∈ {-2017; -2016; ....; 2017; 2018}
Tổng các số nguyên x là :
(-2017) + (-2016) + .... + 2017 + 2018
= 2018 + [(-2017) + 2017] + [(-2016) + 2016] + ....
= 2018 + 0 + 0 + ....
= 2018
b) a + 3 ≤ x ≤ a + 2018 (a ∈ N)
x ∈ {a + 3; a + 4; ...; a + 2018}
Tổng các số nguyên x là :
a + 3 + a + 4 + .... + a + 2018
(2018 - 3) : 1 + 1 = 2016
= 2016a + (3 + 4 + .... + 2018)
(2018 + 3) . 2016 : 2 = 2037168
= 2016a + 2037168
3. Tìm x ∈ Z biết:
a) (x + 1) + (x + 3) + (x + 5) + …+ (x + 99) = 0
= (x + x + ... + x) + (1 + 3 + 5 + ... + 99) = 0
(99 - 1) : 2 + 1 = 50
(99 + 1) . 50 : 2 = 2500
x . 50 + 2500 = 0
x . 50 = -2500
x = -50
b) (x – 3) + (x - 2) + (x – 1 ) + … + 10 + 11 = 11
(x – 3) + (x - 2) + (x – 1 ) + … + 10 = 0
[(x – 3) + (x - 2) + (x – 1 )] + (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) = 0
[(x – 3) + (x - 2) + (x – 1 )] + 55 = 0
(x – 3) + (x - 2) + (x – 1 ) = -55
x + x + x + (-3 - 2 - 1) = -55
3x + (-6) = -55
3x = -49
x = -49/3
c) x + (x + 1) + (x + 2) + ..... + 2018 + 2019 = 2019
x + (x + 1) + (x + 2) + ..... + 2018 = 0
(2018 - x) : 1 + 1 = 2019 - x
(2018 + x) : 2
⇒ (2019 - x) . [(2018 + x) : 2] = 0
✽ 2019 - 2019 = 0
⇒ x = 2019 (loại vì x = 2019 thì số số hạng sẽ là 0)
✽ 2018 + (-2018) = 0
⇒ x = -2018 (nhận)
x = -2018
\(2^2.\left(x+3^2\right)-5=55\)
\(4.\left(x+9\right)-5=55\)
\(4.\left(x+9\right)=55+5\)
\(4.\left(x+9\right)=100\)
\(x+9=100:4\)\(\)
\(x+9=25\)
\(x=25-9\)
\(x=16\)
\(7.\left(x+5^2\right)-20=190\)
\(7.\left(x+25\right)-20=190\)
\(7.\left(x+25\right)=190+20\)
\(7.\left(x+25\right)=210\)
\(x+25=210:7\)
\(x+25=30\)
\(x=30-25\)
\(x=5\)
\(6.\left(x+2^3\right)+40=100\)
\(6.\left(x+8\right)+40=100\)
\(6.\left(x+8\right)=100-40\)
\(6.\left(x+8\right)=60\)
\(x+8=60:6\)
\(x+8=10\)
\(x=10-8\)
\(x=2\)
\(95-5.\left(x+2\right)=45\)
\(5.\left(x+2\right)=95-45\)
\(5.\left(x+2\right)=50\)
\(x+2=50:5\)
\(x+2=10\)
\(x=10-2\)
\(x=8\)
\(15.x-133=17\)
\(15.x=17+133\)
\(15.x=150\)
\(x=150:15\)
\(x=10\)
\(14.x+54=82\)
\(14.x=82-54\)
\(14.x=28\)
\(x=28:14\)
\(x=2\)
1/ 2/ 3/ 4/
22(x + 32) - 5 = 55 7(x + 52) - 20 = 190 6(x + 23) + 40 = 100 95 - 5(x + 2) = 45
4(x + 9) - 5 = 55 7(x + 25) - 20 = 190 6(x + 6) + 40 = 100 5(x + 2) = 95 - 45
4(x + 9) = 55 + 5 7(x + 25) = 190 + 20 6(x + 6) = 100 - 40 5(x + 2) = 50
4(x + 9) = 60 7(x + 25) = 210 6(x + 6) = 60 x + 2 = 50 : 5
x + 9 = 60 : 4 x + 25 = 210 : 7 x + 6 = 60 : 6 x + 2 = 10
x + 9 = 15 x + 25 = 30 x + 6 = 10 x = 10 - 2
x = 15 - 9 x = 30 - 25 x = 10 - 6 x = 8
x = 6 x = 5 x = 4
5/ 6/
15x - 133 = 17 14x + 54 = 82
15x = 17 + 133 14x = 82 - 54
15x = 150 14x = 28
x = 150 : 15 x = 28 : 14
x = 10 x = 2
\(a,70-5\times\left(x-3\right)=45\)
\(5\times\left(x-3\right)=70-45\)
\(5\times\left(x-3\right)=25\)
\(x-3=25:5\)
x - 3 = 5
x = 5 + 3 = 8
vậy x = 8
\(b,12+\left(5+x\right)=20\)
12 + 5 + x = 20
17 + x = 20
x = 20 - 17 = 3
vậy x = 3
c, 130 - (100 + x) = 25
130 - 100 - x = 25
30 - x = 25
x = 30 - 25 = 5
vậy x = 5
\(g,10+2\times x=4^5:4^3\)
\(10+2\times x=4^2\)
\(10+2\times x=16\)
\(2\times x=16-10\)
\(2\times x=6\)
x = 6 : 2 = 3
vậy x = 3
h, \(14\times x+54=82\)
\(14\times x=82-54\)
\(14\times x=28\)
\(x=28:14=2\)
vậy x = 2
\(k,15\times x-133=17\)
\(15\times x=17+133\)
\(15\times x=150\)
\(x=150:15=10\)
vậy x = 10