lỗi rồi

lỗi

lại lỗi

A = 60

bn cứ tính từ trái sang phải là đc òi

mk nha

A=41,54-4,18+23,17+8,46-5,81-3,17

A= 37,36.      +.   31,63.      -    2,64

A=.      68,99.                      -     2,64

A=.                      66,35.     ( hok tốt)

A=(41.54-4.18)+(23.17+8.46)-(5.82-3.17)

A=37.36+31.63-2.65

A=68.99-2,65

A=66.34

nho h cho minh nhe(:

a)3Fe+2O₂→Fe₃O₄.

b)2Fe+3Cl₂→2FeCl₃.

c)CH₄+2O₂→CO₂+2H₂O.

\(a,3Fe+2O_2\rightarrow^{t^o}Fe_3O_4\\ 3:2:1\\ b,2Fe+3Cl_2\rightarrow^{t^o}2FeCl_3\\ 2:3:2\\ c,CH_4+2O_2\rightarrow^{t^o}CO_2+2H_2O\\ 1:2:1:2\)

\(\left(x-y\right)^5:\left(y-x\right)^3\Leftrightarrow\left(x-y\right)^5:-\left(x-y\right)^3=-\left(x-y\right)^2\)

\(a,=2x\left(2x+3y\right)\\ b,=3x\left(x^2-9\right)=3x\left(x-3\right)\left(x+3\right)\\ c,=x\left(x-7y\right)+\left(x-7y\right)=\left(x+1\right)\left(x-7y\right)\\ d,=\left(x+y\right)^2-9z^2=\left(x+y-3z\right)\left(x+y+3z\right)\)

a. 5x + 10y = 5(x + 2y)

b. 3x³ - 12x

= 3x(x² - 4)

= 3x(x - 2)(x + 2)

c. 4x² + 9x - 4xy - 9y

= 4x² - 4xy + 9x - 9y

= 4x(x - y) + 9(x - y)

= (4x + 9)(x - y)

d. 3x² + 5y - 3xy - 5x

= 3x² - 3xy - 5x + 5y

= 3x(x - y) - 5(x - y)

= (3x - 5)(x - y)

e. 3y² - 3z² + 3x² + 6xy

= 3x² + 6xy + 3y² - 3z²

= 3(x² + 2xy + y² - z²)

= \(3\left[\left(x+y\right)^2-z^2\right]\)

= \(3\left(x+y+z\right)\left(x+y-z\right)\)

a) \(=5\left(x+2y\right)\)

b) \(=3x\left(x^2-4\right)=3x\left(x-2\right)\left(x+2\right)\)

c) \(=4x\left(x-y\right)+9\left(x-y\right)=\left(x-y\right)\left(4x+9\right)\)

d) \(=3x\left(x-y\right)-5\left(x-y\right)=\left(x-y\right)\left(3x-5\right)\)

e) \(=3\left[\left(x^2+2xy+y^2\right)-z^2\right]=3\left[\left(x+y\right)^2-z^2\right]\)

\(=3\left(x+y-z\right)\left(x+y+z\right)\)

\(a,=5\left(x+2y\right)\\ b,=3x\left(x^2-4\right)=3x\left(x-2\right)\left(x+2\right)\\ c,=x\left(4x+9\right)-y\left(4x+9\right)=\left(x-y\right)\left(4x+9\right)\\ d,=3x\left(x-y\right)-5\left(x-y\right)=\left(x-y\right)\left(3x-5\right)\)