tìm x biết
x - 30%x + 4x - 1/3 = 1/2 : 7/8
x + 2x + 3x + ... + 9x = 459 - 32
( x - 23) : 14 + 25 = 42 - 12018
Bài 1 : Tìm số tự nhiên hỏ nhất khác 0 biết a chia hết cho 40, 220, 24.
Bài 2 : Tìm x
a) (x-23) : 14+ 25 = 42-12002
b) 23.x +20020.x = 995 -15:3
c) x+2x +3x....+9x= 459-32
Bài 3:
a) Tính S = 4+ 7+ 10+ 13+ ............+2014
b) Chứng minh rằng n.(n+2013) chia hết cho 2 với mọi số tự nhiên n
1) (4-3x) (10x-5)=0
2) (7-2x) (4+8x) = 0
3) (9-7x) (11-3x) = 0
4) (7-14x) (x-2) = 0
5) (2x+1) (x-3) = 0
6) (8-3x) (-3x+5) = 0
7) (16-8x) (2-6x) = 0
8) (x+4) (6x-12) = 0
9) (11-33x) (x+11) = 0
10) (x-1/4) (x+5/6) = 0
11) (7/8-2x) (3x+1/3) = 0
12) 3x - 2x^2 = 0
13) 5x + 10x^2 = 0
14) 4x + 3x^2 = 0
15) -8x^2 + x =0
16) 10x^2 - 15x = 0
17) x^2 -4 =0
18) 9 - x^2 = 0
19) x^2 -1 = 0
20) (x-3) (2x-1) = (2x-1) ( 2x+3)
21) (5+4x) (-x+2) = (5+4x) (7+5x)
22) (4+x) (x-5) = (3x-8) (x-5) = 0
23) (3x-8) (7-21x) - (9+2x) (7-21x)
24) (10+ 7x) (x+1) = (9x-2)(x-1)
25) (9x-4) (x-1/2) - (x-1/2) (6+x) = 0
26) 9x^2 - 1 = (3x-1) (x+4)
27) (x+7) (3x+1) = 49-x^2
28) (2x+1)^2 = (x-1)^2
29)x^3- 5x^2+6x = 0
30) 3x^2 + 5x + 2 = 0
Giảii giúpp mìnhh đyy mọii ngườii .
\(\left(4-3x\right)\left(10x-5\right)=0\)
\(\Rightarrow\orbr{\begin{cases}4-3x=0\\10x-5=0\end{cases}\Rightarrow\orbr{\begin{cases}3x=4\\10x=5\end{cases}\Rightarrow}\orbr{\begin{cases}x=\frac{4}{3}\\x=\frac{1}{2}\end{cases}}}\)
\(\left(7-2x\right)\left(4+8x\right)=0\)
\(\Rightarrow\orbr{\begin{cases}7-2x=0\\4+8x=0\end{cases}\Rightarrow\orbr{\begin{cases}2x=7\\8x=-4\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{7}{2}\\x=-\frac{1}{2}\end{cases}}}}\)
rồi thực hiện đến hết ...
Brainchild bé ngây thơ qus e , ko thực hiện đến hết như thế đc đâu :>
\(\left(x-3\right)\left(2x-1\right)=\left(2x-1\right)\left(2x+3\right)\)
\(2x^2-7x+3=4x^2+4x-3\)
\(2x^2-7x+3-4x^2-4x+3=0\)
\(-2x^2-11x+6=0\)
\(2x^2+11x-6=0\)
\(2x^2+12x-x-6=0\)
\(2x\left(x+6\right)-\left(x+6\right)=0\)
\(\left(x+6\right)\left(2x-1\right)=0\)
\(x+6=0\Leftrightarrow x=-6\)
\(2x-1=0\Leftrightarrow2x=1\Leftrightarrow x=\frac{1}{2}\)
\(3x-2x^2=0\)
\(x\left(2x-3\right)=0\)
\(x=0\)
\(2x-3=0\Leftrightarrow2x=3\Leftrightarrow x=\frac{3}{2}\)
Tự lm tiếp nha
tìm x
17x – ( -16x – 37) = 2x +
-2x –3. (x – 17) = 34 – 2(-x + 25
17x + 3. ( -16x – 37) = 2x + 43 - 4x
103 -57: [-2. (2x – 1)2 – (-9)0] = -106
3x – 32 > -5x + 1
15 + 4x < 2x – 145
-3. (2x + 5) -16 < -4. (3 – 2x)
-2x + 15 < 3x – 7 < 19 – x
x + (x+1) + (x+2) + (x+3) + .... + 13 + 14 = 14
25 + 24 + 23 +...+ x + (x - 2) + (x – 3) = 25
17x + 3. ( -16x – 37) = 2x + 43 - 4x
<=>17x-48x-111=-2x+43
<=>-29x=154
<=> \(x=-\frac{154}{29}\)
-3. (2x + 5) -16 < -4. (3 – 2x)
\(\Leftrightarrow-6x-31< -12+8x.\)
\(\Leftrightarrow-14x< 19\Rightarrow x< -\frac{19}{14}\)
lên mạng xem ik
hỏi google là đc hết mak
1. Tìm x, biết:
a.x-(32-37)=3x-(32+x)
b.45-(2x-37)= -x-54
c.42-(3-x)=25-34
d.(25+2x)-34=x-54
2.Tìm x, biết:
a.8x-75=5x+21
b.9x+25= -(2x-58)
c.|2x+1|=|-5|
d.3.(x-2)+4.( -2+x)=6.(x-2)
3. Tính giá trị biểu thức
a.ax+ay+bx+by với a+b= -2 và x+y=17
b.ax-ay+bx-by với a+b=-7 và x-y=-1
: Tìm x, biết:
a) 3x( 4x- 1) - 2x(6x- 3 )=30 b) 2x(3-2x) + 2x(2x-1)=15
c) (5x-2)(4x-1) + (10x +3)(2x - 1)=1 d) (x+2) (x+2)- (x -3)(x+1) = 9
e) (4x+1)(6x-3) = 7 + (3x – 2)(8x + 9) g) (10x+2)(4x- 1)- (8x -3)(5x+2) =14
`@` `\text {Ans}`
`\downarrow`
`a)`
`3x(4x-1) - 2x(6x-3) = 30`
`=> 12x^2 - 3x - 12x^2 + 6x = 30`
`=> 3x = 30`
`=> x = 30 \div 3`
`=> x=10`
Vậy, `x=10`
`b)`
`2x(3-2x) + 2x(2x-1) = 15`
`=> 6x- 4x^2 + 4x^2 - 2x = 15`
`=> 4x = 15`
`=> x = 15/4`
Vậy, `x=15/4`
`c)`
`(5x-2)(4x-1) + (10x+3)(2x-1) = 1`
`=> 5x(4x-1) - 2(4x-1) + 10x(2x-1) + 3(2x-1)=1`
`=> 20x^2-5x - 8x + 2 + 20x^2 - 10x +6x - 3 =1`
`=> 40x^2 -17x - 1 = 1`
`d)`
`(x+2)(x+2)-(x-3)(x+1)=9`
`=> x^2 + 2x + 2x + 4 - x^2 - x + 3x + 3=9`
`=> 6x + 7 =9`
`=> 6x = 2`
`=> x=2/6 =1/3`
Vậy, `x=1/3`
`e)`
`(4x+1)(6x-3) = 7 + (3x-2)(8x+9)`
`=> 24x^2 - 12x + 6x - 3 = 7 + (3x-2)(8x+9)`
`=> 24x^2 - 12x + 6x - 3 = 7 + 24x^2 +11x - 18`
`=> 24x^2 - 6x - 3 = 24x^2 + 18x -11`
`=> 24x^2 - 6x - 3 - 24x^2 + 18x + 11 = 0`
`=> 12x +8 = 0`
`=> 12x = -8`
`=> x= -8/12 = -2/3`
Vậy, `x=-2/3`
`g)`
`(10x+2)(4x- 1)- (8x -3)(5x+2) =14`
`=> 40x^2 - 10x + 8x - 2 - 40x^2 - 16x + 15x + 6 = 14`
`=> -3x + 4 =14`
`=> -3x = 10`
`=> x= - 10/3`
Vậy, `x=-10/3`
Bài 1 : tì x thuộc z
a) -12(x-5)+7(3-x)=5
b) 30(x+2)-6(x-5)-24x=100
c) (x-23):14+25=42-1^2002
d) (x-5^6)= (x-5^4)
e) 2^3.x+2002^0.x=995-15:3
g) x+2x+3x+....+9x=459-3^2
h) 13x+(-3^2x) = 2003^1+1^2003
k) 2^5x+3^3x= 6.100-10.205^0
l) x-6:2-(48-24):2:6-3=0
bài 2 tìm x thuộc z
a) /x/=/x+8/
b)/x/=/x/
c)/x/+/x/=0
các bạn giúp mình nhé
\(a,-12\left(x-5\right)+7\left(3-x\right)=5\)
\(-12x+60+21-7x=5\)
\(-12x-7x=5-60-21\)
\(-19x=-76\Leftrightarrow x=4\)
\(b,30\left(x+2\right)-6\left(x-5\right)-24x=100\)
\(30x+60-6x+30-24x=100\)
\(30x-6x-24x=100-60-30\)
\(0x=10\left(vl\right)\)
Vậy pt vô nghiệm
\(c,\left(x-23\right):14+25=42-1^{2002}\)
\(\left(x-23\right).\frac{1}{14}+25=42-1\)
\(\frac{x}{14}-\frac{23}{14}+25=41\)
\(\frac{x}{14}-\frac{23}{14}=16\)
\(\frac{x}{14}=\frac{247}{14}\)
\(x=247\)
tìm x biết
a) (6x-3) (2x+4) + (4x-1) (5-3x) = -21
b) 6x (3x+5) - 2x (9x-2) + (17-x) (x-1) + x (x-18) =0
c) (15-2x) (4x+1) - (13-4x) (2x-3) - (x-1) (x+2) + x2=52
d) (8x-3) (3x+2) - (4x+7) (x+4) = (2x+1) (5x-1) - 33
Rút gọn hết ta được :
a/ 41x - 17 = -21
=> 41x = -4 => x = 4/41
b/ 34x - 17 = 0
=> 34x = 17
=> x = 17/34 = 1/2
c/ 19x + 56 = 52
=> 19x = -4
=> x = -4/19
d/ 20x2 - 16x - 34 = 10x2 + 3x - 34
=> 10x2 - 19x = 0
=> x(10x - 19) = 0
=> x = 0
hoặc 10x - 19 = 0 => 10x = 19 => x = 19/10
Vậy x = 0 ; x = 19/10
Rút gọn hết ta được :
a/ 41x - 17 = -21
=> 41x = -4 => x = 4/41
b/ 34x - 17 = 0
=> 34x = 17
=> x = 17/34 = 1/2
c/ 19x + 56 = 52
=> 19x = -4
=> x = -4/19
d/ 20x 2 - 16x - 34 = 10x 2 + 3x - 34
=> 10x 2 - 19x = 0
=> x(10x - 19) = 0
=> x = 0 hoặc 10x - 19 = 0
=> 10x = 19
=> x = 19/10
Vậy x = 0 ; x = 19/10
a) ( 6x - 3 ) ( 2x + 4 ) + ( 4x - 1 ) ( 5 - 3x ) = -21
<=> 12x2 + 24x - 6x - 12 + 20x - 12x2 - 5 + 3x = -21
<=> 41x = -21 + 12 + 5
<=> 41x = -4
<=> x = -4/41
Tìm x , biết
a)x+2x+3x+...+9x=459 - 9
b)x+(x+1)+(x+2)+...+(x+30)=1240
a,x+x2+x3+....+x9=459-9
<=>x(1+2+3+...+9)=450
<=>x45=450
<=>x=10
b ,thì tương tự nhé b
28 giây trước (15:57)
Tìm x , biết
a)x+2x+3x+...+9x=459 - 9
45x = 450
x= 10
---------
b)x+(x+1)+(x+2)+...+(x+30)=1240
31x + (1 +2 + 3 ....+ 30 ) =1240
31x + 456 = 1240
31x = 784
x= 784/31
a)\(x+2x+3x+...+9x=459-9\)
\(x+2x+3x+...+9x=450\)
\(x\left(1+2+3+...+9\right)=450\)
\(45x=450\)
\(x=450\div45\)
\(x=10\)
b)\(x+\left(x+1\right)+\left(x+2\right)+...+\left(x+30\right)=1240\)
\(x+x+1+x+2+...+x+30=1240\)
\(\left(x+x+x+...+x\right)+\left(1+2+3+...+30\right)=1240\)
\(31x+465=1240\)
\(31x=1240-465\)
\(31x=775\)
\(x=775\div31\)
\(x=25\)
\(\frac{4}{-25x^2+20x-3}=\frac{3}{5x-1}-\frac{2}{5x-3}\)
\(\frac{1}{x^2-3x+2}+\frac{1}{x^2-5x+6}-\frac{2}{x^2-4x+3}=0\)
\(\frac{x-1}{2x^2-4x}-\frac{7}{8x}=\frac{5-x}{4x^2-8x}-\frac{1}{8x-16}\)
\(\frac{1}{x^2+9x+20}+\frac{1}{x^2+11x+30}+\frac{1}{x^2+13x+42}=\frac{1}{18}\)