a) \(x\) x 4 = 41
b) \(x\)x 6 = 63
c) \(x\) x 2 = 13
giúp mik hai bài này nha
Bài 1 (1,5 điểm): Thực hiện phép tính
a) 19.25 + 19.16 + 41
b) 12 : {390 : [500 - (125 + 35.7)]}
c) [1800 – (43 – 18.3)3] : 8 + 22
Bài 2 (2 điểm): Tìm x nguyên
a) x – 65 = 38 – 58
b) 3(x + 6) – 53 = 2(x – 8) – 1
c) (2 + x)3 – 23 = 41
Bài 2:
a: =>x-65=-20
hay x=45
Bài 3: Tìm x, biết:
a) 6/13 : (1/2 + x) = 15/39 b) 3 x (x/4 + x/28 + x/70 + x/130 ) = 60/13
a) \(\dfrac{6}{13}:\left(\dfrac{1}{2}-x\right)=\dfrac{15}{39}\)
\(\dfrac{1}{2}-x=\dfrac{6}{13}:\dfrac{15}{39}\)
\(\dfrac{1}{2}-x=\dfrac{6}{5}\)
\(x=\dfrac{1}{2}-\dfrac{6}{5}\)
\(x=-\dfrac{7}{10}\)
b) \(3\times\left(\dfrac{x}{4}+\dfrac{x}{28}+\dfrac{x}{70}+\dfrac{x}{130}\right)=\dfrac{60}{13}\)
\(3\times x\times\left(\dfrac{1}{4}+\dfrac{1}{28}+\dfrac{1}{70}+\dfrac{1}{130}\right)=\dfrac{60}{13}\)
\(x\times\left(\dfrac{3}{1\times4}+\dfrac{3}{4\times7}+\dfrac{3}{7\times10}+\dfrac{3}{7\times13}\right)=\dfrac{60}{13}\)
\(x\times\left(1-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{10}+\dfrac{1}{10}-\dfrac{1}{13}\right)=\dfrac{60}{13}\)
\(x\times\left(1-\dfrac{1}{13}\right)=\dfrac{60}{13}\)
\(x\times\dfrac{12}{13}=\dfrac{60}{13}\)
\(x=\dfrac{60}{13}:\dfrac{12}{13}\)
\(x=5\)
Bài 13: Tìm x biết: a) (x-2)(x-3)-D0. b) (x-3)(x-4)-0. c) (x-7)(6-x)=0. d) (x-3)(x-13)=0. The Bài 14: Tìm x biết: a) (12-x)(2-x)=0. b) (x-33)(11-x)=0. c) (21-x)(12-x)=0. d) (50-x)(x-150) =0. Bài 15: Tìm x biết: a) 2x +x = 45. b) 2x +7x = 918. c) 2x+3x 60+5. d) 11x+22x 33.2.
bài 1:tìm x biết
a) x + 1/9 - 3/5= 3/6 b) 3/4 - x + 6/-11 = 5/6
bài 2: tìm x biết
a) x : 13/16= 5/-8 b) x . -14/28 = 6/-9 - 2/15
c) -12/25 . (3/4 -x + 6/-11 - 5/6) = 0 d) x: 4/28 = 13/-19 + 8/25
bài 3:tìm x biết
a) 62/7.x= 29/9:3/56 b) 1/5:x=1/5+1/7 c)1/2a2+1 : x=2
Bài 1 tìm x biết
a> x=7/25+-1/5
b> x=5/11+4/-9
c> x/3=2/3+-1/7
d> x/5=5/6+-19/30
e> x/6=3/2+-7/15
Bài 2 cộng các phân số sau
a> -650/1430+588/686
b> 2004/2010+8/-670
Bài 3 tìm x biết
a> -5/13+-4/13 < x/13 < 2/13+-7/13
b> 3/2+-1/3 <x/6 < 1/9+31/18
c> -5/19+3/19 < x/19 bé hơn hoặc bằng 13/19+-11/19
d> -7/8+5/6 bé hơn hoặc bằng x/24 bé hơn hoặc bằng 5/8+-5/12
Bài 1 :
\(a)x=\frac{7}{25}+\left(-\frac{1}{5}\right)\)
\(x=\frac{2}{25}\)
\(b)x=\frac{5}{11}+\left(\frac{4}{-9}\right)\)
\(x=\frac{1}{99}\)
Mấy câu kia dễ tự làm :>
bài 9 :
6 mũ 2 x 73 + 36 x 3 mũ 3
197 -[ 6 x ( 5 - 1) mũ 2 +2022 mũ 0 ] : 5
bài 10: tìm số tự nhiên biết x
21- 4 . x = 13
30 : ( x - 3 ) + 1 = 4 mũ 5 : 4 mũ 3
( x - 1 ) mũ 3 + 5 . 6 = 38
Bài 9,
62x73+36x33=36x73+36x27=36(73+27)=36x100=3600.
197-\([\)6x(5-1)2+20220\(]\):5=197-\([\)6x16+1\(]\):5=197-97:5=197-97/5=888/5.
Bài 10,
21-4x=13
=>4x=21-13=8
=>x=8:4=2.
30:(x-3)+1=45:43=42=16
=>30:(x-3)=16-1=15
=>x-3=30:15=2
=>x=2+3=5.
(x-1)3+5x6=38
=>(x-1)3+30=38
=>(x-1)3=38-30=8=23
=>x-1=2
=>x=3.
bài 7 tìm x
1,x(x+3)-5(x+3)=0 2,5x(x-1)=x-1
3,(x+1)=(x+1)\(^2\) 4,x(2x-3)-2(3-2x)=0
5,\(\left(x-2\right)^2-4=0\) 6,\(36x^2=49\)
7,\(2x\left(x-6\right)-x+6=0\) 8,\(3x\left(2x-1\right)-24x+12=0\)
9,\(x^2-6x+8=0\) 10,\(x^2+2x-15=0\)
1: =>(x+3)(x-5)=0
=>x=5 hoặc x=-3
2: =>(x-1)(5x-1)=0
=>x=1/5 hoặc x=1
5: =>(x-4)*x=0
=>x=0 hoặc x=4
10: =>(x+5)(x-3)=0
=>x=3 hoặc x=-5
9: =>(x-2)(x-4)=0
=>x=2 hoặc x=4
7: =>(x-6)(2x-1)=0
=>x=1/2 hoặc x=6
8: =>(2x-1)(3x-12)=0
=>x=4 hoặc x=1/2
bài 13: tìm x biết
a. 124 + (118 - x) = 217
b. 156- (x + 61) = 82
c. 219 - 7(x + 1) = 100
d. (3x - 6). 3 = 3^4
e. 231 - (x - 6) = 1339 : 13
a) 124 + (118 - x) = 217
118 - x = 217 - 124
118 - x = 93
x = 118 - 93
x = 25
b) 156 - (x + 61) = 82
x + 61 = 156 - 82
x + 61 = 74
x = 74 - 61
x = 13
c) 219 - 7(x + 1) = 100
7(x + 1) = 219 - 100
7(x + 1) = 119
x + 1 = 119 : 7
x + 1 = 17
x = 17 - 1
x = 16
d) (3x - 6).3 = 3⁴
3x - 6 = 3⁴ : 3
3x - 6 = 3³
3x - 6 = 27
3x = 27 + 6
3x = 33
x = 33 : 3
x = 11
e) 231 - (x - 6) = 1339 : 13
231 - (x - 6) = 103
x - 6 = 231 - 103
x - 6 = 128
x = 128 + 6
x = 134
a) 124 + (118 - x) = 217
118 - x = 217 - 124
118 - x = 93
x = 118 - 93
x = 25
b) 156 - (x + 61) = 82
x + 61 = 156 - 82
x + 61 = 74
x = 74 - 61
x = 13
c) 219 - 7(x + 1) = 100
7(x + 1) = 219 - 100
7(x + 1) = 119
x + 1 = 119 : 7
x + 1 = 17
x = 17 - 1
x = 16
d) (3x - 6) . 3 = 34
(3x - 6) . 3 = 81
(3x - 6) = 81 : 3
(3x - 6) = 27
3x = 27 + 6
3x = 33
x = 33 : 3
x = 11
e) 231 - (x - 6) = 1339 : 13
231 - (x - 6) = 103
(x - 6) = 231 - 103
x - 6 = 128
x = 128 + 6
x = 134
cô cấm dùng máy tính -)
lớp 9 ms đc dùng:_)
bài 2: tìm x biết
a) ( x + 1 ).( 3 - x ) > 0
b) ( 4x - 3 ).( 5 - x ) < 0
c) 3/( x - 4 ).( x - 7 ) + 6/( x - 7 ).( x - 13 ) + 15/( x - 13 ).( x - 28 ) - 1/( x - 28 ) = -5/2
ai làm nhanh mk tk cho 3 cái
a) Ta có : ( x + 1 ).( 3 - x ) > 0
Th1 : \(\hept{\begin{cases}x+1>0\\3-x>0\end{cases}\Rightarrow\hept{\begin{cases}x>-1\\x>3\end{cases}\Rightarrow}x>3}\)
Th2 : \(\hept{\begin{cases}x+1< 0\\3-x< 0\end{cases}\Rightarrow\hept{\begin{cases}x< -1\\x< 3\end{cases}\Rightarrow}x< -1}\)
Bài 1: Tìm x:
1) (x-3)3 -( x-3)(x2+ 3x+9) +6( x+1)2+ 3x2 = -33
2) (X-3)( X2+ 3X+9) - X(X-2)( 2+X) = 1
3) (X+2)(X2 - 2X+4) – X(X-3)(X+3) = 26
a: Ta có: \(\left(x-3\right)^3-\left(x-3\right)\left(x^2+3x+9\right)+6\left(x+1\right)^2+3x^2=-33\)
\(\Leftrightarrow x^3-9x^2+27x-27-x^3+27+6x^2+12x+1+3x^2=-33\)
\(\Leftrightarrow39x=-34\)
hay \(x=-\dfrac{34}{39}\)
b: Ta có: \(\left(x-3\right)\left(x^2+3x+9\right)-x\left(x-2\right)\left(x+2\right)=1\)
\(\Leftrightarrow x^3-27-x^3+4x=1\)
\(\Leftrightarrow4x=28\)
hay x=7
c: Ta có: \(\left(x+2\right)\left(x^2-2x+4\right)-x\left(x-3\right)\left(x+3\right)=26\)
\(\Leftrightarrow x^3+8-x^3+9x=26\)
\(\Leftrightarrow x=2\)