Rút gọn A
3x-5/x^2-4+2x/x+2-3/2-x
Giúp mình :((
Những câu hỏi liên quan
Bài 10.Rút gọn biểu thức:
a)(-x+1).(x2-2)-(1-x3-x2)
b)-4.(x+3).(x+4)+4x2-5x
c)(2x+3).(1-x)-(2x-1).3x
d)(x-1)2-(x-1).(-5x)
e)2x(x-3)+(x-2).(5-2x)
f)2(x-5).(2x+3)-(x-3).(x+1)
Giúp mình với mình cảm ơn mn ạ
P/s : Ai làm được mấy bài ở đây thì giúp mình nhé. Chứ mình bất lực lắm rồi :(( Bài 1 Rút gọn 1 ) 2x . ( x - 5 ) + ( x - 2 ) . ( x + 3 )2) ( 2x - ) . ( 1 - x ) - ( x - 3 ) . ( -2 x )3) ( 4x - 3 ) . ( 4x - 3 ) - ( 3x + 2 ) . ( 3x - 2 )4) ( 2x - 1 ) . ( 2x + 1 ) - 4 . ( x2 + 1 )5) 3x ( 2x - 8 ) - ( 2 - 6x ) . ( 5 + x )6 ) x . ( 3x - 18 ) . ( x - 4 ) . ( x - 2 ) + 8Bài 2 Tìm x1 ) 3 x . ( x - 2 ) - 3 x2 12 ) x . ( 6x - 5 ) - 3x . ( 2x - 3 ) 73 ) x . ( 2x - 1 ) + 2 . ( 1 - x2 ) 04 ) 5 . ( x2 -1 )...
Đọc tiếp
P/s : Ai làm được mấy bài ở đây thì giúp mình nhé. Chứ mình bất lực lắm rồi :((
Bài 1 Rút gọn
1 ) 2x . ( x - 5 ) + ( x - 2 ) . ( x + 3 )
2) ( 2x - ) . ( 1 - x ) - ( x - 3 ) . ( -2 x )
3) ( 4x - 3 ) . ( 4x - 3 ) - ( 3x + 2 ) . ( 3x - 2 )
4) ( 2x - 1 ) . ( 2x + 1 ) - 4 . ( x2 + 1 )
5) 3x ( 2x - 8 ) - ( 2 - 6x ) . ( 5 + x )
6 ) x . ( 3x - 18 ) . ( x - 4 ) . ( x - 2 ) + 8
Bài 2 Tìm x
1 ) 3 x . ( x - 2 ) - 3 x2 = 1
2 ) x . ( 6x - 5 ) - 3x . ( 2x - 3 ) = 7
3 ) x . ( 2x - 1 ) + 2 . ( 1 - x2 ) = 0
4 ) 5 . ( x2 -1 ) + x . ( 1 - 5 x ) = x - 2
5 ) 3x . ( 4x - 1 ) - ( 2x + 1 ) . ( 5 + 6x ) = 0
6 ) ( x + 3 ) . ( 2x - 1 ) - ( x - 4 ) . ( 2x + 1 ) = 10
7 ) ( 3x + 4 ) . ( 2x - 1 ) + 6x . ( 1 - x ) = 0
8 ) 2x . ( x2 - 1 ) + x . ( 1 - 3x - 2x2 ) = -x - 27
7: Ta có: \(\left(3x+4\right)\left(2x-1\right)+6x\left(1-x\right)=0\)
\(\Leftrightarrow6x^2-3x+8x-4+6x-6x^2=0\)
\(\Leftrightarrow11x=4\)
hay \(x=\dfrac{4}{11}\)
8: Ta có: \(2x\left(x^2-1\right)+x\left(-2x^2-3x+1\right)=-x-27\)
\(\Leftrightarrow2x^3-2x-2x^3-3x^2+x+x+27=0\)
\(\Leftrightarrow x^2=9\)
hay \(x\in\left\{3;-3\right\}\)
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Rút gọn
a, (3x-5)^2 - (2x-3)^2 + (4-2x).(2x+4)
b, ( 5x-7)^2 - ( 4x -3).(2x+3)^2- (x-3).(3x^2-5)
..... Giúp mình nha.... Toán 8 nè..... :D
a. \(A=9x^2-30x+25-4x^2+12x-9+16-4x^2\)
\(=x^2-18x+32\)
b. \(B=25x^2-70x+49-\left(4x+3\right)\left(4x^2+12x+9\right)-3x^3+9x^2+5x-15\)
\(=25x^2-70x+49-\left(16x^3+48x^2+36x-12x^2-36x-27\right)-3x^3+9x^2+5x-15\)
\(=-19x^3+-2x^2-65x+61\)
Chúc em học tốt ^^
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bài 1 rút gọn biểu thức
a) (2x-5)^2-4x(x+3)
b) (x-2)^3 -6(x+4)(x-4)-(x-2)(x^2+2x+4)
c)(x-1)^2-2(x-1)(x+2)+(x+2)^2+5(2x-3)
bài 2 rút gọn biểu thức
a)(2-3x)^2-5x(x-4)+4(x-1)
b)(3-x)(x^2+3x+9)+(x-3)^3
c)(x-4)^2(x+4)-(x-4)(x+4)^2+3(x^2-16)
1:
a: \(\left(2x-5\right)^2-4x\left(x+3\right)\)
\(=4x^2-20x+25-4x^2-12x\)
=-32x+25
b: \(\left(x-2\right)^3-6\left(x+4\right)\left(x-4\right)-\left(x-2\right)\left(x^2+2x+4\right)\)
\(=x^3-6x^2+12x-8-\left(x^3-8\right)-6\left(x^2-16\right)\)
\(=-6x^2+12x-6x^2+96=-12x^2+12x+96\)
c: \(\left(x-1\right)^2-2\left(x-1\right)\left(x+2\right)+\left(x+2\right)^2+5\left(2x-3\right)\)
\(=\left(x-1-x-2\right)^2+5\left(2x-3\right)\)
\(=\left(-3\right)^2+5\left(2x-3\right)\)
\(=9+10x-15=10x-6\)
2:
a: \(\left(2-3x\right)^2-5x\left(x-4\right)+4\left(x-1\right)\)
\(=9x^2-12x+4-5x^2+20x+4x-4\)
\(=4x^2+12x\)
b: \(\left(3-x\right)\left(x^2+3x+9\right)+\left(x-3\right)^3\)
\(=27-x^3+x^3-9x^2+27x-27\)
\(=-9x^2+27x\)
c: \(\left(x-4\right)^2\left(x+4\right)-\left(x-4\right)\left(x+4\right)^2+3\left(x^2-16\right)\)
\(=\left(x-4\right)\left(x+4\right)\left(x-4-x-4\right)+3\left(x^2-16\right)\)
\(=\left(x^2-16\right)\left(-8\right)+3\left(x^2-16\right)\)
\(=-5\left(x^2-16\right)=-5x^2+80\)
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Giúp mình với ạ Rút gọn 2x^4+11x^3+11x^2-24x-36/x^5+7x^4+21x^3+47x^2+80x+60
Rút gọn biểu thức:
a)(x+2)2 +x(x-4)
b)(x-3)2 -(x+3)(x-4)
c)(3x+1)2+3x(2-4x)
d)(2x-4y)2 -(2x-3)(2x-3y)
Mình cần gấp nha
a) (x+2)2+x(x-4)
=x2+4x+4+x2-4x
=2x2+4
b)(x-3)2-(x+3)(x-4)
=x2-6x+9-x2+4x-3x+12
=-5x+12
c) (3x+1)2+3x(2-4x)
=9x2+6x+1+6x-12x2
=-3x2+12x+1
d) (2x-4y)2-(2x-3)(2x-3y)
=4x2-16xy+16y2-4x2+6xy+6x-9y
=16y2-10xy+6x-9y
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(x+5).(x-4)-(x+2)^2+(2x+3)^3= (4x^2+1)+18(2x+3) rút gọn
Bài 19 Rút gọn
1) (x+2)^2+(3-x)^2
2) (4-x)^2 -(x-3)^2
3) (x-5)(x+5)-(x+5)^2
4) (x-3)^2-(x-4)(x+4)
5) (y^2 -6y+9)-(3-y)^2
6. (2x+3)² –(2x–3).(2x+3)
1) Ta có: \(\left(x+2\right)^2+\left(x-3\right)^2\)
\(=x^2+4x+4+x^2-6x+9\)
\(=2x^2-2x+13\)
2) Ta có: \(\left(4-x\right)^2-\left(x-3\right)^2\)
\(=\left(4-x-x+3\right)\left(4-x+x-3\right)\)
\(=-2x+7\)
3) Ta có: \(\left(x-5\right)\left(x+5\right)-\left(x+5\right)^2\)
\(=x^2-25-x^2-10x-25\)
=-10x-50
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4) Ta có: \(\left(x-3\right)^2-\left(x-4\right)\left(x+4\right)\)
\(=x^2-6x+9-x^2+16\)
=-6x+25
5) Ta có: \(\left(y^2-6y+9\right)-\left(y-3\right)^2\)
\(=y^2-6y+9-y^2+6y-9\)
=0
6) Ta có: \(\left(2x+3\right)^2-\left(2x-3\right)\left(2x+3\right)\)
\(=4x^2+12x+9-4x^2+9\)
=12x+18
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Bài 19 rút gọn
1) (x+2)^2+(3-x)^2
2) (4-x)^2-(x-3)^2
3) (x-5)(x+5)-(x+5)^2
4)(x-3)^2-(x-4)(x+4)
5) (y^2-6y+9)-(3-y)^2
6) (2x+3)^2-(2x-3)(2x+3)
1) Ta có: \(\left(x+2\right)^2+\left(x-3\right)^2\)
\(=x^2+4x+4+x^2-6x+9\)
\(=2x^2-2x+13\)
2) Ta có: \(\left(4-x\right)^2-\left(x-3\right)^2\)
\(=\left(4-x-x+3\right)\left(4-x+x-3\right)\)
\(=\left(-2x+7\right)\cdot1\)
\(=-2x+7\)
3) Ta có: \(\left(x-5\right)\left(x+5\right)-\left(x+5\right)^2\)
\(=x^2-25-x^2-10x-25\)
\(=-10x-50\)
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