Rút gọn :
(2x + 1)2 + (3x – 1)2 + 2(2x +1)(3x – 1)
Rút gọn biểu thức sau: (2x + 1)2 + (3x – 1)2 + 2(2x + 1)(3x – 1)
(2x + 1)2 + (3x – 1)2 + 2(2x + 1)(3x – 1)
= (2x + 1)2 + 2.(2x + 1)(3x – 1) + (3x – 1)2
= [(2x + 1) + (3x – 1)]2
= (2x + 1 + 3x – 1)2
= (5x)2
= 25x2
rút gọn: A=2x^2(3x+4)(3x-4)_9/2(2x^2+1)(2x^2-1)
\(A=2x^2\left(3x+4\right)\left(3x-4\right)-\dfrac{9}{2}\left(2x^2+1\right)\left(2x^2-1\right)\)
\(=2x^2\left(9x^2-16\right)-\dfrac{9}{2}\left(4x^4-1\right)\)
\(18x^4-32x^2-18x^4+\dfrac{9}{2}\\ =-32x^2+\dfrac{9}{2}\)
Ta có: \(A=2x^2\left(3x+4\right)\left(3x-4\right)-\dfrac{9}{2}\left(2x^2+1\right)\left(2x^2-1\right)\)
\(=2x^2\left(9x^2-16\right)-\dfrac{9}{2}\left(4x^4-1\right)\)
\(=18x^4-36x^2-18x^4+\dfrac{9}{2}\)
\(=-36x^2+\dfrac{9}{2}\)
Rút gọn
-3x(2x+1)+(2x-1)(3x+2)
`-3x(2x+1)+(2x-1)(3x+2)`
`=-6x^2-3x+6x^2+4x-3x-2`
`=(6x^2-6x^2)+(4x-3x-3x)-2`
`=-2x-2`
A = \(-6x^2-3x+\left(6x^2+x-2\right)\)
= \(-2x-2\)
Rút gọn : -3x ( 2x + 1 ) + ( 2x - 1 ) ( 3x + 2 )
Ta có: \(-3x\left(2x+1\right)+\left(2x-1\right)\left(3x+2\right)\)
\(=-6x^2-3x+6x^2+4x-3x-2\)
\(=-2x-2\)
\(-3x\left(2x+1\right)+\left(2x-1\right)\left(3x+2\right)\)
\(=-6x^2-3x+6x^2+x-2\)
\(=-2x-2\)
Rút gọn (2x+1)*(2x-1)-(3x+1)2-(3x-2)*(5-2x)
(2x+1)*(2x-1)-(3x+1)2-(3x-2)*(5-2x)
=4x2-1-(9x2+6x+1)-(15x-6x2-10+4x)
=4x2-1-9x2-6x-1-15x+6x2+10-4x
=x2-25x+8
rút gọn biểu thức:
a) \(\dfrac{2x^{2^{ }}-2x}{x-1}\)
b)\(\dfrac{x^{2^{ }}+2x+1}{3x^2+3x}\)
c)\(\dfrac{x}{3x-3}+\dfrac{1}{x^2-1}\)
a) Ta có: \(\dfrac{2x^2-2x}{x-1}\)
\(=\dfrac{2x\left(x-1\right)}{x-1}\)
=2x
b) Ta có: \(\dfrac{x^2+2x+1}{3x^2+3x}\)
\(=\dfrac{\left(x+1\right)^2}{3x\left(x+1\right)}\)
\(=\dfrac{x+1}{3x}\)
c) Ta có: \(\dfrac{x}{3x-3}+\dfrac{1}{x^2-1}\)
\(=\dfrac{x}{3\left(x-1\right)}+\dfrac{1}{\left(x-1\right)\left(x+1\right)}\)
\(=\dfrac{x+1+3}{3\left(x-1\right)\left(x+1\right)}\)
\(=\dfrac{x+4}{3x^2-3}\)
a, \(\dfrac{2x^2-2x}{x-1}=\dfrac{2x\left(x-1\right)}{x-1}=2x\) ( đk : \(x\ne1\) )
b,\(\dfrac{x^2+2x+1}{3x^2+3x}=\dfrac{\left(x+1\right)^2}{3x\left(x+1\right)}=\dfrac{x+1}{3x}\) ( đk : \(x\ne-1\) )
c
=
rút gọn biểu thức
(3x+1)^2+ 2(3x+1).(2x-1)+(2x-1)^2
\(\left(3x+1\right)^2+2\left(3x+1\right)\left(2x-1\right)+\left(2x-1\right)^2=\left(3x+1+2x-1\right)^2=25x^2\)
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
rút gọn các biểu thức sau a.x^2-1/x^2+2x+1 b.x^2-1/x^2-2x+1 c.1/3x-2 - 1/3x+2 - 3x-6/4-9x^2
a: \(=\dfrac{\left(x-1\right)\left(x+1\right)}{\left(x+1\right)^2}=\dfrac{x-1}{x+1}\)
b: \(=\dfrac{\left(x-1\right)\cdot\left(x+1\right)}{\left(x-1\right)^2}=\dfrac{x+1}{x-1}\)
c: \(=\dfrac{3x+2-3x+2+3x-6}{\left(3x-2\right)\left(3x+2\right)}=\dfrac{3x-2}{\left(3x-2\right)\left(3x+2\right)}=\dfrac{1}{3x+2}\)
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