Tìm x
24 - ( 18 - 6x ) = 3x + 36
Bài4:Tìm x:
a. 124 + (118 – x) = 217 b. 7x – 8 = 713 c. x- 36:18 = 12 d. (x- 36):18 = 12 e. (x-47) -115 = 0 f. 315 + (146 – x) = 401 | g. (6x – 39 ) : 3 = 201 h. 23 + 3x = 56 : 53 i. 5x + x = 39 – 311:39 j. 7x – x = 521 : 519 + 3.22 - 70 k. 7x – 2x = 617: 615 + 44 : 11 l. 0 : x = 0 | m. 3x = 9 n. 4x = 64 o. 2x = 16 p. 9x- 1 = 9 q. x4 = 16 r. 2x : 25 = 1 |
Bài4:Tínhnhanh
1. 58.75 + 58.50 – 58.25 2. 27.39 + 27.63 – 2.27 3. 128.46 + 128.32 + 128.22 4. 87.23 + 13.93 + 70.87
| 5. 12.35 + 35.182 – 35.94 6. 48.19 + 48.115 + 134.52 7. 27.121 – 87.27 + 73.34 8. 136.23 + 136.17 – 40.36 9. 125.98 – 125.46 – 52.25 | 10. 17.93 + 116.83 + 17.233 11. 5.23 + 35.41 + 64.65 12. 29.87 – 29.23 + 64.71 13. 19.27 + 47.81 + 19.20
|
b: Ta có: 7x-8=713
nên 7x=721
hay x=103
c: Ta có: x-36:18=12
nên x-2=12
hay x=14
d: Ta có: (x-36):18=12
nên x-36=216
hay x=252
a. 124 + (118 – x) = 217
118 - x = 93
- x = - 25
x = 25
b. 7x – 8 = 713
7x =721
x =103
c. x- 36:18 = 12
x- 2 =12
x =14
d. (x- 36):18 = 12
x-36 = 216
x = 252
e. (x-47) -115 = 0
x-47 = 115
x = 162
f. 315 + (146 – x) = 401
146-x =86
-x = -60
x = 60
g. (6x – 39 ) : 3 = 201
6x - 39 = 603
6x = 642
x = 107
h. 23 + 3x = 56 : 53
23 +3x = 125
3x = 102
x=34
21. \(x^2\)- 3x\(\sqrt{y}\)+ 2y
22. x + 2\(\sqrt{x-1}\)
23. \(\sqrt{x^3}\)- 2\(\sqrt{x}\)-x
24. -6x + 5\(\sqrt{x}\)+ 1
22: \(x+2\sqrt{x-1}=\left(\sqrt{x-1}+1\right)^2\)
24: \(-6x+5\sqrt{x}+1=\left(\sqrt{x}-1\right)\left(-6\sqrt{x}-1\right)\)
21: \(x^2-3x\sqrt{y}+2y\)
\(=x^2-x\sqrt{y}-2x\sqrt{y}+2y\)
\(=x\left(x-\sqrt{y}\right)-2\sqrt{y}\left(x-\sqrt{y}\right)\)
\(=\left(x-\sqrt{y}\right)\left(x-2\sqrt{y}\right)\)
23: \(\sqrt{x^3}-2\sqrt{x}-x\)
\(=x\sqrt{x}-2\sqrt{x}-x\)
\(=\sqrt{x}\left(x-\sqrt{x}-2\right)\)
\(=\sqrt{x}\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)\)
Tìm P biết P + 4 x − 12 x 3 − 3 x 2 − 4 x + 12 = 3 x − 3 − x 2 4 − x 2
A. P = x x + 3
B. P = x x - 3
C. P = 2 x x − 3
D. P = x − 3 x
Tìm P biết: P + 4x − 12 x 3 − 3x 2 − 4x + 12 = 3 x − 3 − x 2 4 − x 2
A. P = x x + 3
B. P = x x − 3
C. P = 1 x − 3
D. P = x-3 x
tính bằng cách nhanh nhất
36/11 x22/17 x51/72 =
22/16 x 64/55 x27/13=
36x 48/ 12 x24 +18 x104/36x4=
36/11 x 22/17 x 51/72
= 36 x 22 x 51/11 x 17 x 72
= 36 x 2 x 11 x 17 x 3/11 x 17 x 36 x 2
= 3
22/16 x 64/55 x 27/13
= 22 x 64 x 27/16 x 55 x 13
=2 x 11 x 16 x 4 x 27/16 x 5 x 11 x 13
= 216/65
36 x 48/12 x 24 + 18 x 104/36 x 4
= 12 x 3 x 2 x 24/12 x 24 + 18 x 13 x 2 x 4/ 18 x 2 x 4
= 6 + 13
= 19
=
Quy đồng mẫu thức sau:
5x2 / x3 - 6x2 và 3x+18 / x2 - 36
\(\frac{5x^2}{x^3-6x^2}=\frac{5x^2}{x^2\left(x-6\right)}=\frac{5}{x-6}\\ \frac{3x+18}{x^2-36}=\frac{3\left(x+6\right)}{\left(x-6\right)\left(x+6\right)}=\frac{3}{x-6}\)
Tìm nghiệm của đa thức
a, 3x ² - 6x + 36 = C
b, -2x ² + 4x -7 = D
c, -x ² + x - 4= E
Cả ba đa thức này đều vô nghiệm hết bạn ơi
Tìm x, bết:
6x (3x+5) - 2x (3x-2) + (17-x) (x-1) + x (x-18) =0
6x(3x + 5) - 2x(3x - 2) + (17 - x)(x - 1) + x(x - 18) = 0
=> (18x2 - 6x2 - x2 + x2) + (30x + 4x - 16x - 18x) - 17 = 0
=> 12x2 - 17 = 0
=> 12x2 = 17
=> x2 = 17/12
=> \(\orbr{\begin{cases}x=\sqrt{\frac{17}{12}}\\x=-\sqrt{\frac{17}{12}}\end{cases}}\)
\(6x\left(3x+5\right)-2x\left(3x-2\right)+\left(17-x\right)\left(x-1\right)+x\left(x-18\right)=0\)
\(\Leftrightarrow9x^2+30x-6x^2+4x+17x-17-x^2+x+x^2-18x=0\)
\(\Leftrightarrow3x^2+34x-17=0\) ( vô nghiệm )
6x( 3x + 5 ) - 2x( 3x - 2 ) + ( 17 - x )( x - 1 ) + x( x - 18 ) = 0
<=> 18x2 + 30x - 6x2 + 4x - x2 + 18x - 17 + x2 - 18x = 0
<=> 12x2 + 34x - 17 = 0
\(\Delta'=b'^2-ac=\left(\frac{b}{2}\right)^2-ac=\left(\frac{34}{2}\right)^2-12\cdot\left(-17\right)=289+204=493\)( không muốn xài Delta nữa đâu nhưng ... :)) )
\(\Delta'>0\)nên phương trình đã cho có hai nghiệm phân biệt
\(\hept{\begin{cases}x_1=\frac{-b'+\sqrt{\Delta'}}{a}=\frac{-17+\sqrt{493}}{12}\\x_2=\frac{-b'-\sqrt{\Delta'}}{a}=\frac{-17-\sqrt{493}}{12}\end{cases}}\)
Vậy ...
(3x+2)x24=192
(3\(x\) + 2) x 24 = 192
3\(x\) + 2 = 192 : 24
3\(x\) + 2 = 8
3\(x\) = 8 - 2
3\(x\) = 6
\(x\) = 2
(3x+2).24=192
3x+2 =192:24
3x+2 =8
3x =8-2
3x =6
x =6:3
x = 2
Vậy x =2