Thực hiện phép tính: x 4 x − 2 5 + 3 x
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
\(\dfrac{5x+2}{x^2-4}+\dfrac{x-5}{x-2}=\dfrac{5x+2+x^2-3x-10}{\left(x-2\right)\left(x+2\right)}\\ =\dfrac{x^2+2x-8}{\left(x-2\right)\left(x+2\right)}=\dfrac{\left(x+4\right)\left(x-2\right)}{\left(x-2\right)\left(x+2\right)}=\dfrac{x+4}{x+2}\\ \left(x+4\right)^2-\left(x+3\right)\left(x-2\right)=-13\\ \Leftrightarrow x^2+8x+16-x^2+x+6=-13\\ \Leftrightarrow9x=-13-22=-35\\ \Leftrightarrow x=-\dfrac{35}{9}\)
V . CÁC PHÉP TOÁN VỀ PHÂN THỨC :
Bài 1 : Thực hiện các phép tính sau :
b) x+3/x-2+4+x/2-x
Bài 2 : Thức hiện các phép tính sau :
a) x+1/2x+6+2x+3/x2+3x
d) 3/2x2y +5/xy2 + x/y3
e) x/x-2y +x/x+2y + 4xy/4y2-x2
g) x+3/x+1 +2x-1/x-1 +x+5/X2-1 ;
Bài 1:
b: \(=\dfrac{x+3-4-x}{x-2}=\dfrac{-1}{x-2}\)
Bài 2:
a: \(=\dfrac{x+1}{2\left(x+3\right)}+\dfrac{2x+3}{x\left(x+3\right)}\)
\(=\dfrac{x^2+x+4x+6}{2x\left(x+3\right)}=\dfrac{x^2+5x+6}{2x\left(x+3\right)}=\dfrac{x+2}{2x}\)
d: \(=\dfrac{3}{2x^2y}+\dfrac{5}{xy^2}+\dfrac{x}{y^3}\)
\(=\dfrac{3y^2+10xy+2x^3}{2x^2y^3}\)
e: \(=\dfrac{x^2+2xy+x^2-2xy-4xy}{\left(x+2y\right)\left(x-2y\right)}=\dfrac{2x^2-4xy}{\left(x+2y\right)\cdot\left(x-2y\right)}=\dfrac{2x}{x+2y}\)
Thực hiện phép tính:
(x+5)^2+(x-2)^2-4(x-3)(x+3)
(x+5)2+(x-2)2-4(x-3)(x+3)
=x2+10x+25+x2-4x+4-4x2+36
=x2+x2-4x2+10x-4x+25+4+36
=-2x2+6x+65
thực hiện phép tính 4/(x-3)+5/(x+3)-(13-9x^2)/(x^2-9)
cau hoi nay de lam ma
\(\frac{4}{x-3}+\frac{5}{x+3}-\frac{13-9x^2}{x^2-9}\)
ĐKXĐ : \(x\ne\pm3\)
\(=\frac{4}{x-3}+\frac{5}{x+3}-\frac{13-9x^2}{\left(x+3\right)\left(x-3\right)}\)
\(=\frac{4\left(x+3\right)}{\left(x+3\right)\left(x-3\right)}+\frac{5\left(x-3\right)}{\left(x+3\right)\left(x-3\right)}-\frac{13-9x^2}{\left(x+3\right)\left(x-3\right)}\)
\(=\frac{4x+12}{\left(x+3\right)\left(x-3\right)}+\frac{5x-15}{\left(x+3\right)\left(x-3\right)}-\frac{13-9x^2}{\left(x+3\right)\left(x-3\right)}\)
\(=\frac{4x+12+5x-15-13+9x^2}{\left(x+3\right)\left(x-3\right)}\)
\(=\frac{9x^2+9x-16}{\left(x+3\right)\left(x-3\right)}=\frac{9x^2+9x-16}{x^2-9}\)
nhung cau hoi rat de ma cau nay a , khong hieu sao dap an la nhung cay cau co so 0 0 0 0 0 0
Thực hiện các phép tính sau:
a) (2x + 3)(x – 5) – (x – 1)^2 + x(7 – x)
b) (x – 4)(x + 4) – (x^3 – 27) : (x – 3)
a/ \(\left(2x+3\right)\left(x-5\right)-\left(x-1\right)^2+x\left(7-x\right)\)
\(=2x^2-2x-15-x^2+2x-1+7x-x^2\)
\(=7x-16\)
b, = x2 - 16 - ( x3 - 33 ) : ( x - 3 )
= x2 - 16 - \([\) ( x - 3 ) ( x2 + 3x + 9 ) \(]\) : ( x - 3 )
= x2 - 16 - ( x2 + 3x + 9 )
= x2 - 16 - x2 - 3x - 9
= -25 - 3x
\(a,=2x^2-10x+3x-15-x^2+2x-1+7x-x^2=2x-16\\ b,=x^2-16-\left(x-3\right)\left(x^2+3x+9\right):\left(x-3\right)\\ =x^2-16-x^2-3x-9=-3x-25\)
Thực hiện phép tính sau: a) (4-x^2)/(x-3)+(2x-2x^2)/(3-x)+(5-4x)/(x-3). b) 2/(x+2)+(-4)/(2-x)+(5x+2)/(4-x^2).
a: \(\dfrac{4-x^2}{x-3}+\dfrac{2x-2x^2}{3-x}+\dfrac{5-4x}{x-3}\)
\(=\dfrac{4-x^2-2x+2x^2+5-4x}{x-3}=\dfrac{x^2-6x+9}{x-3}\)
=(x-3)^2/(x-3)
=x-3
b: \(\dfrac{2}{x+2}+\dfrac{-4}{2-x}+\dfrac{5x+2}{4-x^2}\)
\(=\dfrac{2}{x+2}-\dfrac{4}{x-2}-\dfrac{5x+2}{x^2-4}\)
\(=\dfrac{2x-4-4x-8-5x-2}{\left(x-2\right)\left(x+2\right)}=\dfrac{-7x-14}{\left(x-2\right)\left(x+2\right)}\)
=-7(x+2)/(x-2)(x+2)
=-7/(x-2)
Thực hiện phép tính :
1.(2x+3).(x-5)+2x(3-x)+x-10
2.(-x-2)3+(2x-4).(x2+2x+4)-x2.(x-6)
1.(2x+3).(x-5)+2x(3-x)+x-10
=2x^2 -10x+3x-15+6x-2x^2+x-10
=2x-25
2.(-x-2)3+(2x-4).(x2+2x+4)-x2.(x-6)
=-x^3+6x^2-12x-8+2x^3+4x^2+8x-4x^2+8x-16-x^3+6x^2
thực hiện phép tính 2 x^ 2 y^ 2 .(- 4 x^ 5 y^3)kết quả là
Thực hiện phép tính
(x-1) * ( x^5+x^4+x^3+x^2+x+1)