Thực hiện phép tính C = 2 x 2 + 4 x + 8 x 3 − 3 x 2 − x + 3 : x 3 − 8 ( x + 1 ) ( x − 3 )
A. C = ( x − 1 ) ( x − 2 ) 2
B. C = 1 ( x − 1 ) ( x − 2 )
C. C = − 2 ( x − 1 ) ( x − 2 )
D. C = 2 ( x − 1 ) ( x − 2 )
thực hiện phép tính :
b ( x + 2 ) ( x^2 - 2x + 4 )
c ( 4x^ - 8x^2 + 13x - 5 ) : ( 2x -1 )
b. (x + 2)(x2 - 2x + 4)
= x3 - 2x2 + 4x + 2x2 - 4x + 8
= x3 + 8
c: \(\dfrac{4x^3-8x^2+13x-5}{2x-1}=\dfrac{4x^3-2x^2-6x^2+3x+10x-5}{2x-1}\)
=2x^2-3x+5
Thực hiện phép tính
(2+x)*(x^2-4)-(x-2)*(x^2+2x+4)
\(\left(2+x\right)\left(x^2-4\right)-\left(x-2\right)\left(x^2+2x+4\right)=\left(x+2\right)^2\left(x-2\right)-\left(x-2\right)\left(x^2+2x+4\right)=\left(x-2\right)\left[\left(x+2\right)^2-x^2-2x-4\right]=\left(x-2\right)\left(x^2+4x+4-x^2-2x-4\right)=\left(x-2\right)2x=2x^2-4x\)
\(\left(x+2\right)\left(x^2-4\right)-\left(x-2\right)\left(x^2+2x+4\right)\)
\(=x^3-4x+2x^2-8-x^3+8\)
\(=2x^2-4x\)
Thực hiện phép tính: a) 5x²(3x²-7x+2) b) (x+3)(x²-1) c) 3x.(x²+3x-4)
a) \(5x^2\left(3x^2-7x+2\right)\)
\(=5x^2.3x^2+5x^2.\left(-7x\right)+5x^2.2\)
\(=\left(5.3\right)\left(x^2.x^2\right)+\left[5.\left(-7\right)\right].\left(x^2.x\right)+\left(5.2\right).x^2\)
\(=15x^{2+2}+\left(-35\right).x^{2+1}+10.x^2\)
\(=15x^4-35x^3+10x^2\)
Câu 1: Thực hiện phép tính: 90:{9-130 - (15-10) }
A.
В. 3
C. 4
D. 5
Câu 2: Thực hiện phép tính: 3º5 : 393 – 12021 2020
A. 7
В.
C.
D. 10
Câu 3: Tim x biết 2x - 10 = 210
А. 100
В. 110
C. 120
D. 130
Câu 4: Tim x biết : 125 – 12(x-8) = 5 :5I 2022 2021
A. 19
В. 20
С. 5
D. 18
Câu 5: Thực hiện phép tính: (2021-2025) +11".11:11" -20°
A. 136
В. 140
C. 144
D. 150
thực hiện phép tính :
( x - 2 ) * ( x^2 + 2x + 4 ) - ( x^3 + 5 )
\(\left(x-2\right)\left(x^2+2x+4\right)-\left(x^3+5\right)\)
\(=x^3-8-x^3-5\)
=-13
\(\left(x-2\right)\cdot\left(x^2+2x+4\right)-\left(x^3+5\right)\\ =x^2-8-x^3-5\\ =-13\)
thực hiện phép tính: 5x+2/x^2-4+x-5/x-2
x: (x+4)^2-(x+3)(x-2)=-13
\(\dfrac{5x+2}{x^2-4}+\dfrac{x-5}{x-2}=\dfrac{5x+2+x^2-3x-10}{\left(x-2\right)\left(x+2\right)}\\ =\dfrac{x^2+2x-8}{\left(x-2\right)\left(x+2\right)}=\dfrac{\left(x+4\right)\left(x-2\right)}{\left(x-2\right)\left(x+2\right)}=\dfrac{x+4}{x+2}\\ \left(x+4\right)^2-\left(x+3\right)\left(x-2\right)=-13\\ \Leftrightarrow x^2+8x+16-x^2+x+6=-13\\ \Leftrightarrow9x=-13-22=-35\\ \Leftrightarrow x=-\dfrac{35}{9}\)
thực hiện các phép tính sau:
a) x(x^2+4x+5)-x^2(x+4)
b) (x-2)^2+(3-x)(x-1)
c) (x+2)^3-x(x^2+6x+12)
a) \(x\left(x^2+4x+5\right)-x^2\left(x+4\right)\)
\(=x^3+4x^2+5x-x^3-4x^2\)
\(=5x\)
b) \(\left(x-2\right)^2+\left(3-x\right)\left(x-1\right)\)
\(=x^2-4x+4+3x-3-x^2+x\)
\(=1\)
c) \(\left(x+2\right)^3-x\left(x^2+6x+12\right)\)
\(=x^3+6x^2+12x+8-x^3-6x^2-12x\)
\(=8\)
Thực hiện phép tính:
\(\dfrac{x+1}{x^2-4}:\dfrac{x+1}{x+2}\)
\(\dfrac{x+1}{x^2-4}:\dfrac{x+1}{x+2}=\dfrac{x+1}{\left(x-2\right)\left(x+2\right)}:\dfrac{x+1}{x+2}=\dfrac{x+1}{\left(x-2\right)\left(x+2\right)}.\dfrac{x+2}{x+1}=x-2\)
3. Thực hiện phép tính:
a. 5/(2x ^ 2 * y) + 2/(3xy) - y/(x ^ 3)
b. (2x - 7)/(10x - 4) - (3x + 5)/(4 - 10x)
c. x ^ 2 + 1 - (x ^ 4 - 3x ^ 2)/(x ^ 2 - 1)
a: \(=\dfrac{5}{2x^2y}+\dfrac{2}{3xy}-\dfrac{y}{x^3}\)
\(=\dfrac{5\cdot3\cdot x}{6x^3y}+\dfrac{2\cdot2\cdot x^2}{6x^3y}-\dfrac{6y^2}{6x^3y}\)
\(=\dfrac{15x+4x^2-6y^2}{6x^3y}\)
b: \(=\dfrac{2x-7+3x+5}{10x-4}=\dfrac{5x-2}{10x-4}=\dfrac{1}{2}\)
c: \(=\dfrac{x^4-1-x^4+3x^2}{x^2-1}=\dfrac{3x^2-1}{x^2-1}\)
a) Ta có: \(\left(2x+3\right)^2-4\left(x-2\right)\left(x+2\right)\)
\(=4x^2+12x+9-4\left(x^2-4\right)\)
\(=4x^2+12x+9-4x^2+16\)
\(=12x+25\)
b) Ta có: \(\dfrac{x+6}{x^2-4}-\dfrac{2}{x\left(x+2\right)}\)
\(=\dfrac{x\left(x+6\right)}{x\left(x+2\right)\left(x-2\right)}-\dfrac{2\left(x-2\right)}{x\left(x+2\right)\left(x-2\right)}\)
\(=\dfrac{x^2+6x-2x+4}{x\left(x+2\right)\left(x-2\right)}\)
\(=\dfrac{x^2+4x+4}{x\left(x+2\right)\left(x-2\right)}\)
\(=\dfrac{\left(x+2\right)^2}{x\left(x+2\right)\left(x-2\right)}\)
\(=\dfrac{x+2}{x\left(x-2\right)}\)