Thực hiện phép tính:
a)(2x-3)(2x+3)-(x+5)2-(x-1)(x+2)
b)(-3x2+x+2x3+330):(x+5)
Thực hiện phép tính:
a)2x(3x2 - 5x + 3) b)-2x2(x2 + 5x - 3) c)-1/2x2(2x3 - 4x + 3)
d) (2x - 1)(x2 +5- 4) c) 7x(x - 4) - (7x + 3)(2x2 - x + 4).
a: \(=6x^3-10x^2+6x\)
b: \(=-2x^4-10x^3+6x^2\)
c: \(=-x^5+2x^3-\dfrac{3}{2}x^2\)
d: \(=2x^3+10x^2-8x-x^2-5x+4=2x^3+9x^2-13x+4\)
Bài 1: Thực hiện phép tính:
a) 2x.(3x + 3) b) 5x.(3x2-2x + 1) c) 3x2(2x +4)
d) 5x2.(3x2 + 4x – 1) e) (x-1).(2x +3) f) (x+2).(3x-5)
Bài 2: Tìm x, biết:
a) 3x(x+1) – 3x2 = 6
b) 3x(2x+1) – (3x +1).(2x-3) = 10
Bài 1:
\(a,=6x^2+6x\\ b,=15x^3-10x^2+5x\\ c,=6x^3+12x^2\\ d,=15x^4+20x^3-5x^2\\ e,=2x^2+3x-2x-3=2x^2+x-3\\ f,=3x^2-5x+6x-10=3x^2+x-10\)
Bài 2:
\(a,\Leftrightarrow3x^2+3x-3x^2=6\\ \Leftrightarrow3x=6\Leftrightarrow x=2\\ b,\Leftrightarrow6x^2+3x-6x^2+9x-2x-3=10\\ \Leftrightarrow10x=13\Leftrightarrow x=\dfrac{13}{10}\)
Thực hiện phép tính:
a) 5x+3.(x2-x-1)
b) (5-x).(5+x)-(2x-1)2
c) (x4+2x3+10x-25):(x2+5)
a. 5x + 3(x2 - x - 1)
= 5x + 3x2 - 3x - 3
= 3x2 + 5x - 3x - 3
= 3x2 + 2x - 3
b. (5 - x)(5 + x) - (2x - 1)2
25 - x2 - (4x2 - 4x + 1)
= 25 - x2 - 4x2 + 4x - 1
= 25 - 1 - x2 - 4x2 + 4x
= 24 - 5x2 + 4x
a) \(5x+3\left(x^2-x-1\right)=5x+3x^2-3x-3=3x^2+2x-3\)
b) \(\left(5-x\right)\left(5+x\right)-\left(2x-1\right)^2=25-x^2-4x^2+4x-1=-5x^2+4x+24\)
\(a) 5x+3(x^2-x-1)=5x+3x^2-3x-3\)
\(=3x^2-2x-3\)
\(b)(5-x)(5+x)-(2x-1)^2=25-x^2-4x^2+4x-1\)
\(=-5x^2+4x-24\)
thực hiện phép tính
a, 2x.(3x2+1)
b, (2x3-5x2+6x):2
c, (x-3).(x+5)-x(x+2)
help 30 phút nữa thi rồi
\(a,2x\left(3x^2+1\right)=6x^3+2x\)
\(b,\left(2x^3-5x^2+6x\right):2=x^3-\dfrac{5}{2}x^2+3x\)
\(c,\left(x-3\right)\left(x+5\right)-x\left(x+2\right)=x^2+5x-3x-15-x^2-2x=-15\)
Bài 1: Thực hiện phép tính:
a) x(3x2 – 2x + 5) b) 1/3 x2 y2 (6x + 2/3x2 – y)
c) ( 1/3x + 2)(3x – 6) d) ( 1/3x + 2)(3x – 6)
e) (x2 – 3x + 1)(2x – 5) f) ( 1/2x + 3)(2x2 – 4x + 6)
Bài 2: Tìm x, biết:
a) 3(2x – 3) + 2(2 – x) = –3 b) x(5 – 2x) + 2x(x – 1) = 13
c) 5x(x – 1) – (x + 2)(5x – 7) = 6 d) 3x(2x + 3) – (2x + 5)(3x – 2) = 8
Bài 3: Chứng tỏ rằng giá trị của biểu thức sau không phụ thuộc vào giá trị của biến: a) A = x(2x + 1) – x2 (x + 2) + x3 – x + 3
b) B = (2x + 11)(3x – 5) – (2x + 3)(3x + 7) + 5
Bài 4: Tính giá trị của biểu thức
a) A = 2x( 1/2x2 + y) – x(x2 + y) + xy(x3 – 1) tại x = 10; y = – 1 10
b) B = 3x2 (x2 – 5) + x(–3x3 + 4x) + 6x2 tại x = –5
\(1,\\ a,=3x^3-2x^2+5x\\ b,=2x^3y^2+\dfrac{2}{9}x^4y^2-\dfrac{1}{3}x^2y^3\\ c,=x^2-2x+6x-12=x^2+4x-12\\ 2,\\ a,\Rightarrow6x-9+4-2x=-3\\ \Rightarrow4x=2\Rightarrow x=\dfrac{1}{2}\\ b,\Rightarrow5x-2x^2+2x^2-2x=13\\ \Rightarrow3x=13\Rightarrow x=\dfrac{13}{3}\\ c,\Rightarrow5x^2-5x-5x^2+7x-10x+14=6\\ \Rightarrow-8x=-8\Rightarrow x=1\\ d,\Rightarrow6x^2+9x-6x^2+4x-15x+10=8\\ \Rightarrow-2x=-2\Rightarrow x=1\)
\(3,\\ A=2x^2+x-x^3-2x^2+x^3-x+3=3\\ B=6x^2-10x+33x-55-6x^2-14x-9x-21=-76\)
Bài 4:
b: Ta có: \(B=3x^2\left(x^2-5\right)+x\left(-3x^3+4x\right)+6x^2\)
\(=3x^4-15x^2-3x^3+4x^2+6x^2\)
\(=-5x^2\)
\(=-5\cdot25=-125\)
Thực hiện phép tính:
a) 2x (3x2 + 4x + 1) - 6x3
b) (3x2y2 + 6x2y3 - 12xy) : 3xy
c) 10x / x2 - 4 + 3 / x + 2 - 5/x-2
a) \(=6x^3+8x^2+2x-6x^3=8x^2+2x\)
b) \(=\left[3xy\left(xy+2xy^2-4\right)\right]:3xy=xy+2xy^2-4\)
c) \(=\dfrac{10x}{\left(x-2\right)\left(x+2\right)}+\dfrac{3}{x+2}-\dfrac{5}{x-2}=\dfrac{10x+3\left(x-2\right)-5\left(x+2\right)}{\left(x-2\right)\left(x+2\right)}=\dfrac{8x-16}{\left(x-2\right)\left(x+2\right)}=\dfrac{8\left(x-2\right)}{\left(x-2\right)\left(x+2\right)}=\dfrac{8}{x+2}\)
a, \(=6x^3+12x^2+2x-6x^3\\=12x^2+2x\)
b,
\(=xy+2xy^2-4\)
c,
\(\dfrac{10x}{x^2-4}+\dfrac{3}{x+2}-\dfrac{5}{x-2}\)
\(=\dfrac{10x}{\left(x-2\right)\left(x+2\right)}+\dfrac{3x-6}{\left(x-2\right)\left(x+2\right)}-\dfrac{5x+10}{\left(x-2\right)\left(x+2\right)}\)
\(=\dfrac{10x+3x-6-5x-10}{\left(x-2\right)\left(x+2\right)}=\dfrac{8x-16}{\left(x-2\right)\left(x+2\right)}=\dfrac{8\left(x-2\right)}{\left(x-2\right)\left(x+2\right)}=\dfrac{8}{x+2}\)
Thực hiện phép tính:
a) x.(x+2); b) (3xy-8).(5xy+5); c) (1+x).(x-1); d) (2x-1).(x^2+5-4); e) (6x^5y^2 - 9x^4y^3 + 15x^3y^4): 3x^3y^2 f) (2x3 - 21x2 + 67x - 60) : (x - 5)
f: \(=\dfrac{2x^3-10x^2-11x^2+55x+12x-60}{x-5}=2x^2-11x+12\)
Bài 1. Thực hiện phép tính:
a) 2xy(x2+ xy - 3y2)
b) (x + 2)(3x2 - 4x)
c) (x3 + 3x2 - 8x - 20) : (x + 2)
d) (x + y)2 + (x – y)2 – 2(x + y)(x - y) e) (a + b)3 - (a – b)3 – 2b3
f) 2x2(x – 2)+ 3x(x2 – x – 2) –5(3 – x2)
g) (x – 1)(x – 3) – (4 – x)(2x + 1) – 3x2 + 2x – 5
c: \(=\dfrac{x^3+2x^2+x^2+2x-10x-20}{x+2}\)
\(=x^2+x-10\)
Thực hiện phép tính:
a)(4x4y-7x2y+3y).(2y-3x2y)
b)(x2+3x-\(\dfrac{3}{2}\)x3):(2x)-\(\dfrac{x}{2}\).(1-\(\dfrac{3}{2}\)x)
c)(-2x3-x-3+5x2):(3-2x)
a: \(\dfrac{4x^4y-7x^2y+3y}{-3x^2+2y}\)
\(=\dfrac{4x^4y-4x^2y-3x^2y+3y}{-\left(3x^2-2y\right)}\)
\(=\dfrac{4x^2y\left(x^2-1\right)-3y\left(x^2-1\right)}{-\left(3x^2-2y\right)}\)
\(=\dfrac{y\left(x^2-1\right)\left(4x^2-3\right)}{-\left(3x^2-2y\right)}\)
a) `(4x^4y-7x^2y+3y).(2y-3x^2y)`
`=8x^4y^2-14x^2y^2+6y^2-12x^6y^2+21x^4y^2-9x^2y^2`
`=29x^4y^2-12x^6y^2-23x^2y^2+6y^2`
b) `(x^2+3x-3/2 x^3):2x - x/2 . (1-3/2 x)`
`=(x+3-3/2 x^2):2 - (x/2 - 3/4 x^2)`
`=x/2 + 3/2 - 3/4 x^2 -x/2 +3/4 x^2`
`=3/2`
c) `(-2x^3-x-3+5x^2):(3-2x)`
`=(3-2x)(x^2-x-1) : (3-2x)`
`=x^2-x-1`
1/ Thực hiện phép tính:
a/ x2(x - 2x3)
b/(x2+1).5x
c/(x-2)(x2+2x+4)
d/ (x - 2)(x2+2x+4)
e/ (x2 - 1)(x2+ 1)
f) (2x-1)(3x + 2)(3 - x)