2x + 2x + 1 + 2 x + 2 = 960 - 2x + 3
2x +2x+1+2x+2=960-2x+3
tìm x
\(2^x+2^{x+1}+2^{x+2}=960-2^{x+3}\)
\(\Leftrightarrow2^x+2^{x+1}+2^{x+2}+2^{x+3}=960\)
\(\Leftrightarrow2^x\left(1+2+2^2+2^3\right)=960\)
\(\Leftrightarrow2^x.15=960\)
\(\Leftrightarrow2^x=64\)
\(\Leftrightarrow2^x=2^6\Leftrightarrow x=6\)
Vậy...
2x + 2x + 1 + 2x + 2=960 - 2x + 3
\(2^x+2^{x+1}+2^{x+2}=960-2^{x+3}\\ \Leftrightarrow2^x+2^{x+1}+2^{x+2}+2^{x+3}=960\\ \Leftrightarrow2^x+2^x.2+2^x.2^2+2^x.2^3=960\\ \Leftrightarrow2^x\left(1+2+2^2+2^3\right)=960\\ \Leftrightarrow2^x.15=960\\ \Leftrightarrow2^x=64\\ \Leftrightarrow2^x=2^6\\ \Leftrightarrow x=6\)
Vậy \(x=6\)
Rút gọn :
1. (2x-5)(3x+1)-(x-3)^2+(2x+5)^2-(3x+1)^3
2. (2x-1)(2x+1)-3x-2)(2x+3)-(x-1)^3+(2x+3)^3
3. (x-2)(x^2+2x+4)-(3x-2)^3+(3x-4)^2
4. (7x-1)(8x+2)-(2x-7)^2-(x-4)^3-(3x+1)^3
5. (5x-1)(5x+1)-(x+3)(x^2-3x+9)-(2x+4)^2-(3x-4)^2+(2x-5)^3
6. (4x-1)(x+2)-(2x+5)^2-(3x-7)^2+(2x+3)^3=(3x-1)^3
1: \(=6x^2+2x-15x-5-x^2+6x-9+4x^2+20x+25-27x^3-27x^2-9x-1\)
=-27x^3-18x^2+4x+10
2: =4x^2-1-6x^2-9x+4x+6-x^3+3x^2-3x+1+8x^3+36x^2+54x+27
=7x^3+37x^2+46x+33
5:
\(=25x^2-1-x^3-27-4x^2-16x-16-9x^2+24x-16+\left(2x-5\right)^3\)
\(=8x^3-60x^2+150-125+12x^2-x^3+8x-60\)
=7x^3-48x^2+8x-35
Tính (rút gọn )
1, 2x(3x-1)-(2x+1)(x-3)
2, 3(x^2-2x)-(4x+2)(x-1)
3, 3x(x-5)-(x-2)^2 -(2x+3)(2x-3)
4, (2x-3)^2+(2x-1) (x+4)
1) `2x(3x-1)-(2x+1)(x-3)`
`=6x^2-2x-2x^2+6x-x+3`
`=4x^2+3x+3`
2) `3(x^2-3x)-(4x+2)(x-1)`
`=3x^2-9x-4x^2+4x-2x+2`
`=-x^2-7x+2`
3) `3x(x-5)-(x-2)^2-(2x+3)(2x-3)`
`=3x^2-15x-(x^2-4x+4)-(4x^2-9)`
`=3x^2-15x-x^2+4x-4-4x^2+9`
`=-2x^2-11x+5`
4) `(2x-3)^2+(2x-1)(x+4)`
`=4x^2-12x+9+2x^2+8x-x-4`
`=6x^2-5x+5`
1) |2x - 1| = 5
2) |2x - 1| = |x + 5|
3) |3x + 1| = x - 2
4) |3 - 2x| = x + 2
5) |2x - 1| = 5 - x
6) |- 3x| = x - 2
7) |2 - 3x| = 2x + 1
8) |2x - 1| + |4x ^ 2 - 1| = 0
9) (2x + 5)/(x + 3) + 1 = 4/(x ^ 2 + 2x - 3) - (3x - 1)/(1 - x)
10) (x - 1)/(x + 3) - x/(x - 3) = (7x - 3)/(9 - x ^ 2)
11) 5 + 96/(x ^ 2 - 16) = (2x - 1)/(x + 4) + (3x - 1)/(x - 4)
12) (2x)/(2x - 1) + x/(2x + 1) = 1 + 4/((2x - 1)(2x + 1))
13) (x + 2)/(x - 2) - 1/x = 2/(x ^ 2 - 2x)
14) x/(2x - 6) + x/(2x + 2) = (2x + 4)/(x ^ 2 - 2x - 3)
Tính
a.1/2xy^2 (x^2-6y)
b.(x-2)(2x+3)
c.(x+5)(x^2-2x +3)
d.(2x-3)(x^2-2Tính
a.1/2xy^2 (x^2-6y)
b.(x-2)(2x+3)
c.(x+5)(x^2-2x +3)
d.(2x-3)(x^2-2x+5)
e.(x-2y)(x+2y)
f.(2x-1)(4x^2+2x+1)
g.(2x-1)(4x^2-2x+1)x+5)
e.(x-2y)(x+2y)
f.(2x-1)(4x^2+2x+1)
g.(2x-1)(4x^2-2x+1)
Bài I. Rút gọn các biểu thức sau:
a) 3x(2x+1)+ (2x - 3)(x+1),
b) x(3x - 2)2 + 3(x-2)(x+2)
c) (2x+1)(4x² - 2x+1)-2x(2x+3)(2x - 3)-(x-3)²
a: Ta có: \(3x\left(2x+1\right)+\left(2x-3\right)\left(x+1\right)\)
\(=6x^2+3x+2x^2+2x-3x-3\)
\(=8x^2+2x-3\)
Tìm x)
x(1-2x) +(x-2).(2x-3) = 0
x(2x -4) -2x (x+3) =0
(2x+3)2+(x-3).(2x+3) =0
10y2 -2xy +25 +x2 +30y
(2x-1)2 +(2x+1)2 -2(2x-2)(2x+1) +x = 12
a/
\(\Leftrightarrow x-2x^2+2x^2-3x-4x+6=0\)
\(\Leftrightarrow-6x+6=0\)
\(\Leftrightarrow x=1\)
b/
\(\Leftrightarrow2x^2-4x-2x^2-6x=0\)
\(\Leftrightarrow-10x=0\)
\(\Leftrightarrow x=0\)
c/
\(\Leftrightarrow\left(2x+3\right)\left(2x+3+x-3\right)=0\)
\(\Leftrightarrow3x\left(2x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-\frac{3}{2}\end{matrix}\right.\)
c/
\(\Leftrightarrow\left(x^2-2xy+y^2\right)+\left(9y^2+30y+25\right)=0\)
\(\Leftrightarrow\left(x-y\right)^2+\left(3y+5\right)^2=0\)
\(\Leftrightarrow\left\{{}\begin{matrix}x-y=0\\3x+5=0\end{matrix}\right.\)
\(\Leftrightarrow x=y=-\frac{5}{3}\)
d/
\(\Leftrightarrow4x^2-4x+1+4x^2+4x+1-2\left(4x^2-2x-2\right)+x=12\)
\(\Leftrightarrow8x^2+x+2-8x^2+4x+4=12\)
\(\Leftrightarrow5x=6\)
\(\Leftrightarrow x=\frac{6}{5}\)
Khai triển và thu gọn:
1, x(3x - 1) - 2x(x - 1) - (x - 2)2
2, x(2 + x) - (x - 1)(3 - x)-(3 - x)2
3, (2x - 1)2 - 2(2x - 1)(2x - 3) + (3 - 2x)2
tìm x:
a)3(2x-3)+2(2-x)=-3
b)2x(x2-2)+x2(1-2x)-x2=-12
c)3x(2x+3)-(2x+5)(3x-2)=8
d)4x(x - 1) - 3(x2-5)-x2=(x-3)-(x+4)
e)2(3x-1)(2x+5)-6(2x-1)(x+2)=-6
a: Ta có: \(3\left(2x-3\right)+2\left(2-x\right)=-3\)
\(\Leftrightarrow6x-9+4-2x=-3\)
\(\Leftrightarrow4x=2\)
hay \(x=\dfrac{1}{2}\)