Tìm x
a) 5x - x = 29 - 36 :4 b) (3x -48) . 6 = 33.22+23.32 -122
tim so tu nhien x , biet
a, 5x - x = 29 - 36 : 4
b, ( 3x - 48 ) . 6 = 3 mu 3 . 2 mu 2 + 2 mu 3 . 3 mu 2 - 12 mu 2
c, x thuoc B(6) va 22 < x < hoac = 36
a) \(\Leftrightarrow4x=20\Leftrightarrow x=5\)
b) \(\Leftrightarrow18x-288=27.4+8.9-144\)
\(\Leftrightarrow18x=108+72-144+288=324\)
\(\Leftrightarrow x=18\)
c)Ta có:
\(x\in B\left(6\right)\) và \(22< x\le36\)
mà \(B\left(6\right)=\left\{0;6;12;18;24;30;36;42;48;...\right\}\)
\(\Rightarrow x\in\left\{0;6;12;18;24;30;36;42;48;...\right\}\) và \(22< x\le36\)
\(\Rightarrow x\in\left\{24;30;36\right\}\)
Vậy \(x\in\left\{24;30;36\right\}\)
4. x^2 − 5x + 6
5. x^2+7x+10
6. x + 7√x + 10
7. 3x^4 + 7x^2 + 4
8. x^2-x-2
9. x^6 − x^3 − 2
`4)x^2-5x+6`
`=x^2-2x-3x+6`
`=x(x-2)-3(x-2)=(x-2)(x-3)`
`5)x^2+7x+10`
`=x^2+5x+2x+10`
`=x(x+5)+2(x+5)=(x+5)(x+2)`
`6)x+7\sqrt{x}+10` `ĐK: x >= 0`
`=(\sqrt{x})^2+5\sqrt{x}+2\sqrt{x}+10`
`=\sqrt{x}(\sqrt{x}+5)+2(\sqrt{x}+5)=(\sqrt{x}+5)(\sqrt{x}+2)`
`7)3x^4+7x^2+4`
`=3x^4+3x^2+4x^2+4`
`=3x^2(x^2+1)+4(x^2+1)=(x^2+1)(3x^2+4)`
`8)x^2-x-2`
`=x^2-2x+x-2`
`=x(x-2)+(x-2)=(x-2)(x+1)`
`9)x^6-x^3-2`
`=x^6+x^3-2x^3-2`
`=x^3(x^3+1)-2(x^3+1)`
`=(x^3+1)(x^3-2)`.
Phân tích đa thức thành nhân tử:
tìm x
a) 4(18-5x)-12(3x-7)=15(2x-16)-6(x+14)
b) 5(3x+5)-4(2x-3)=5x+3(2x+12)+1
c) 2(5x-8)-3(4x-5)=4(3x-4)+11
a) \(\Rightarrow72-20x-36x+84=30x-240-6x-84\)
\(\Rightarrow80x=480\Rightarrow x=6\)
b) \(\Rightarrow15x+25-8x+12=5x+6x+36+1\)
\(\Rightarrow4x=0\Rightarrow x=0\)
c) \(\Rightarrow10x-16-12x+15=12x-16+11\)
\(\Rightarrow14x=4\Rightarrow x=\dfrac{2}{7}\)
Bài 1: Tìm số tự nhiên x, biết:
a,36 : [ 7(x - 3) + 4 ] = 24 :23
b,[(6x - 39) : 3 ] . 28 = 5628
c,(2x -7) - (x + 135)=0
d,24 .125 + 52 . 25
e,17 . 27 +17 . 25 + 17 . 48
g,122 + (37 - 3x) = 0
h,(14 - 3x) + (6+x) = 0
A) 4(3x-2)-3(5x+6)=35
B)3x(2x-2)-6(x-4)=122
C) x2 -5x=0
D) /3x-2/(x+1/5)=x+1/5
a, 4.(3\(x\) - 2) - 3.(5\(x\) + 6) = 35
12\(x\) - 8 - 15\(x\) - 18 = 35
\(x\)(12 - 15) - ( 8 + 18) = 35
- 3\(x\) - 26 = 35
3\(x\) = - 26 - 35
3\(x\) = - 61
\(x\) = - \(\dfrac{61}{3}\)
c, \(x^2\) - 5\(x\) = 0
\(x\).(\(x-5\)) =0
\(\left[{}\begin{matrix}x=0\\x-5=0\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=0\\x=5\end{matrix}\right.\)
vậy \(x\) \(\in\) {0; 5}
Tìm x thuộc Z,biết:
a) -152–(3x+1)=(-2).(-3)3
b) x–43=(35–x)-48
c) |5x + 1| =11
d) 4(x +1) –(3x +1)= 14
e) [48+ ( x –3)3] .2 =80
f) ( 2x +7)2 = 36
a) -152 - (3x + 1) = (-2).(-3)3
-152 - 3x - 1 = (-2).(-27)
-3x - 153 = 54
-3x = 54 + 153
-3x = 207
x = -69
b) x - 43 = (35 - x) - 48
x - 43 = 35 - x - 48
x - 43= -x - 13
x = -x - 13 + 43
x = 30 + x
x + x = 30
2x = 30
x = 15
tìm x
a. (2x + 1) ² - (3x - 4) ² = 0
b. 5x ³ - 3x ² + 10x - 6 = 0
a) Ta có: \(\left(2x+1\right)^2-\left(3x-4\right)^2=0\)
\(\Leftrightarrow\left(2x+1-3x+4\right)\left(2x+1+3x-4\right)=0\)
\(\Leftrightarrow\left(5-x\right)\left(5x-3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=5\\x=\dfrac{3}{5}\end{matrix}\right.\)
b) Ta có: \(5x^3-3x^2+10x-6=0\)
\(\Leftrightarrow x^2\left(5x-3\right)+2\left(5x-3\right)=0\)
\(\Leftrightarrow5x-3=0\)
hay \(x=\dfrac{3}{5}\)
Chứng minh biểu thức sau không phụ thuộc vào x
a,A=x.(3x^2-x+5)-(2x^3+3x-16)-x.(x^2-x+2)
b,B=4.(6-x)+x^2.(2+3x)-x.(5x-4)+3x^2.(1-x)
a) A = 3x3 - x2 + 5 - 2x3 - 3x + 16 - x3 + x2 - 2x
A = 21
b) B = 24 - 4x + 2x2 + 3x3 - 5x2 + 4x + 3x2 - 3x3
B = 24
Bạn thấy hay thì tim giúp mik nha. Thx bạn
a) Ta có: \(A=x\left(3x^2-x+5\right)-\left(2x^3+3x-16\right)-x\left(x^2-x+2\right)\)
\(=3x^3-x^2+5x-2x^3-3x+16-x^3+x^2-2x\)
\(=16\)
b) Ta có: \(B=4\left(6-x\right)+x^2\left(2+3x\right)-x\left(5x-4\right)+3x^2\left(1-x\right)\)
\(=24-4x+2x^2+3x^3-5x^2+4x+3x^2-3x^3\)
\(=24\)
Tìm x biết
5x-x=29-36:4
5x-x=29-36:4
4x =20
x =20:4
x =5
Vậy x=5
5x-x=29-36:4
<=>4x=29-36:4
<=>4x=29-9
<=>4x=20
<=>x=5
Vậy...bla bla
\(5.x-x=29-36:4\)
\(5.x-x=29-9\)
\(5.x-x=20\)
\(5.x-x.1=20\)
\(\Rightarrow x.\left(5-1\right)=20\)
\(x.4=20\)
\(\Rightarrow x=5\)