Tìm x, biết:
a, 32x+2=92x+3
b, (x-2016)5=(x-2016)7
Tìm số tự nhiên X , biết:
a) 2448 : [119 - (X - 6)] = 24
b) 2016 - 100 x (X + 11) = 128 : 8
\(a,2448:\left[119-\left(x-6\right)\right]=24\)
\(119-\left(x-6\right)=2448:24\)
\(119-\left(x-6\right)=102\)
\(x-6=119-102\)
\(x-6=17\)
\(x=17+6\)
\(\Rightarrow x=23\)
\(b,2016-100\times\left(x+11\right)=128:8\)
\(2016-100\times\left(x+11\right)=16\)
\(100\times\left(x+11\right)=2016-16\)
\(100\times\left(x+11\right)=2000\)
\(x+11=2000:100\)
\(x+11=20\)
\(x=20-11\)
\(\Rightarrow x=9\)
\(a,2448:\left[119-\left(x-6\right)\right]=24\\ 119-\left(x-6\right)=2448:24\\ 119-\left(x-6\right)=102\\ x-6=119-102\\ x-6=17\\ x=17+6\\ x=23\\ b,2016-100\times\left(x+11\right)=128:8\\ 2016-100\times\left(x+11\right)=16\\ 100\times\left(x+11\right)=2016-16\\ 100\times\left(x+11\right)=2000\\ x+11=2000:100\\ x+11=20\\ x=20-11\\ x=9\)
Câu 3 (1,5 điểm). Tìm x, biết:
a) x + 2006 = 2021
b) 2x – 2016 = 24 x 4
c) 3(2x + 1)3 = 81
a: x=15
c: \(\Leftrightarrow2x+1=3\)
hay x=1
a) \(\Rightarrow x=2021-2006=15\)
b) \(\Rightarrow2x-2016=64\Rightarrow2x=2016+64=2080\Rightarrow x=1040\)
c) \(\Rightarrow\left(2x+1\right)^3=81:3=27\Rightarrow2x+1=3\)
\(\Rightarrow2x=3-1=2\Rightarrow x=1\)
`a) x= 15`
`b) 2x-2016=16\(\times\)4`
`⇔ 2x-2016=64`
`⇔ 2x= 2080`
`⇔ x= 1040`
`c) 3(2x+1)^3 =81`
`⇔ (2x+1)^3 =27`
`⇔ (2x+1)^3 =3^3`
`⇔ 2x+1=3`
`⇔ x= 1`
Câu 2. Tìm số tự nhiên x, biết:
a) a) 7x - 8 = 713
b) b) 2448 : [119 - (x - 6)] = 24
c) c) 2016 – 100.(x + 11) = 27 : 23
a,
7x – 8 = 713
7x = 713 + 8
7x = 721
x = 721 : 7
x = 103.
b,
2448:[119-(x-6)]=24
119-(x-6)= 2448 : 24
119-(x-6)= 102
x-6= 119-102
x-6= 17
x=17+6
x=23
c,
2016 - 100.( x +11 ) = 2^7 : 2^3
2016 - 100.(x+11) = 2^4
2016 - 100.(x+11)=16
100.(x+11) = 2016-16
100.(x+11)=2000
x+11=2000:100
x+11=20
x = 20-11
x = 9
Bài 2. Tìm x biết:
a) 31,5 – x = (18,6 – 12,3) : 3
b) 4.(\(\dfrac{-5}{6}\))−x=\(\dfrac{7}{12}\)+\(\dfrac{-1}{3}\)
c) \(\dfrac{1}{2}\)−\(\dfrac{1}{2}\)x=\(\dfrac{2}{3}\)
a.
31,5 – x = (18,6 – 12,3) : 3
31,5 - x = 2,1
x = 31,5 - 2,1
x = 29,4
b.
???
Bài 2. Tìm x biết:
a) 31,5 – x = (18,6 – 12,3) : 3
31,5 – x = 6,3 : 3
31,5 – x = 2,1
x = 31,5 – 2,1
x = 29,4
b) Đề sai.
bài 2:tìm x,biết:
a)x+3/9=7/6x2/3
b)x-2/3=1/8:5/4
giải ra giúp mik vs ạ! mik cảm ơn...mik đag cần gấp
a: \(x+\dfrac{3}{9}=\dfrac{7}{6}\cdot\dfrac{2}{3}\)
=>\(x+\dfrac{1}{3}=\dfrac{14}{18}=\dfrac{7}{9}\)
=>\(x=\dfrac{7}{9}-\dfrac{1}{3}=\dfrac{7}{9}-\dfrac{3}{9}=\dfrac{4}{9}\)
b: \(x-\dfrac{2}{3}=\dfrac{1}{8}:\dfrac{5}{4}\)
=>\(x-\dfrac{2}{3}=\dfrac{1}{8}\cdot\dfrac{4}{5}=\dfrac{1}{10}\)
=>\(x=\dfrac{1}{10}+\dfrac{2}{3}=\dfrac{3+20}{30}=\dfrac{23}{30}\)
Tìm các số x,y,z biết:
a) x:y = 2:5 và 2x - y = 3
b) x/2 = y/3; y/4 = z/7 và 2x - y + z =50
c) x/2 = y/3 = z/4 và x2 - y2 + 2z2 = 108
Lời giải:
a. Áp dụng TCDTSBN:
\(\frac{x}{y}=\frac{2}{5}\Rightarrow \frac{x}{2}=\frac{y}{5}=\frac{2x}{4}=\frac{y}{5}=\frac{2x-y}{4-5}=\frac{3}{-1}=-3\)
$\Rightarrow x=-3.2=-6; y=-3.5=-15$
b. Áp dụng TCDTSBN:
$\frac{x}{2}=\frac{y}{3}; \frac{y}{4}=\frac{z}{7}$
$\Rightarrow \frac{x}{8}=\frac{y}{12}=\frac{z}{21}$
$=\frac{2x}{16}=\frac{y}{12}=\frac{z}{21}=\frac{2x-y+z}{16-12+21}=\frac{50}{25}=2$
$\Rightarrow x=8.2=16; y=2.12=24; z=2.21=42$
c.
$\frac{x}{2}=\frac{y}{3}=\frac{z}{4}$
$\Rightarrow \frac{x^2}{4}=\frac{y^2}{9}=\frac{z^2}{16}=\frac{2z^2}{32}$
$=\frac{x^2-y^2+2z^2}{4-9+32}=\frac{108}{27}=4$
$\Rightarrow x^2=4.4=16; y^2=9.4=36; z^2=4.4=16$
Kết hợp với đkxđ suy ra:
$(x,y,z)=(4,6,4); (-4; -6; -4)$
Tính: S = 1 - 2 + 3 - 4+ ... + 197 -198 + 199 -200
Tính: P = (-1) + (-2) + (-3) + .... + (-99) + (-100)
Tìm các số nguyên x, biết:
a) x2 - 1 = -54 - 43 - 32 - (-6971) - (-20170)
b) 7(x-1) < 0 và x > -11
c) -10(x - 2016) - 7(x - 2016) - 6(x-2016) - 4(x -2016) - 3(x - 2016) = -30
Tìm x:
15.x+15.2,7=105
x:7=920699:70
5.x-1952=2500-1947
x.2016-x=2016.2017+2016
a)15.x+15.2,7=105
15.(x+2,7)=105
x+2,7=7
x=7-2,7
x=4,3
Vậy x=4,3
b)x:7=920699:70
x:7=920699:10:7
x:7=92069,9:7
x=92069,9
Vậy x=92069,9
c)5.x-1952=2500-1947
5.x-1952=553
5.x=2505
x=501
Vậy x=501
d)x.2016-x=2016.2017+2016
x.(2016-1)=2016.(2017+1)
x.2015=2016.2018
x=\(\frac{2016.2018}{2015}\)
Vậy x\(\frac{2016.2018}{2015}\)
15.x+15.2,7=105
<=> 15.( x + 2,7 ) = 105
=> x + 2,7 = 7
=> x = 7 - 2,7
=> x = 4,3
x:7=920699:70
<=> x . 70 = 920699 . 7
=> x . 70 = 6444893
=> x = 6444893 : 70
=> x = 92069,9
5.x-1952=2500-1947
=> 5x - 1952 = 553
=> 5x = 553 + 1952
=> 5x = 2505
=> x = 2505 : 5
=> x = 501
x.2016-x=2016.2017+2016
=> x ( 2016 - 1 ) = 2016 ( 2017 + 1)
=> x . 2015 = 2016 . 2018
=> x : 2018 = 2016 : 2015
=> x : 2018 = \(\frac{2016}{2015}\)
=> x = \(\frac{2016}{2015}.2018\approx2019\)
Bài 1: Tìm x,y biết:
a) 3-2*x = 3*(5-x)+4
b) 4-(7*x+2017)=6*(5-x)-2017
c) 15-x*(x+1)=4-x^2+2*x
d) -4*(x-5)+2016=3*(8-x)-(2*x-2016)
Ai nhanh mình like cho!