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23 tháng 8 2023

A=8abc+4(ab+bc+ca)+2(a+b+c)+1�=8���+4(��+��+��)+2(�+�+�)+1

A = 8abc + 4ab + 4bc + 4ca + 2a + 2b + 2c + 1

A=(8abc+4ab)+(4bc+2b)+(4ca+2a)+(2c+1)�=(8���+4��)+(4��+2�)+(4��+2�)+(2�+1)

A=4ab(2c+1)+2b(2c+1)+2a(2c+1)+(2c+1)�=4��(2�+1)+2�(2�+1)+2�(2�+1)+(2�+1)

A=(2c+1)(4ab+2a+2b+1)�=(2�+1)(4��+2�+2�+1)

A=(2c+1)[2a(2b+1)+(2b+1)]�=(2�+1)[2�(2�+1)+(2�+1)]

A=(2a+1)(2b+1)(2c+1)

23 tháng 8 2023

A = abc - (ab + bc + ca) + a + b + c - 1

= (abc - ab) - (bc - b) - (ac - a) + (c - 1)

= ab(c - 1) - b(c - 1) - a(c - 1) + (c - 1) 

= (ab - b - a + 1)(c - 1) 

= (a - 1).(b - 1).(c - 1)   

11 tháng 3 2021

Ta có: 

\(A=8abc+4\left(ab+bc+ca\right)+2\left(a+b+c\right)+1\)

\(A=\left(8abc+4ab\right)+\left(4bc+2b\right)+\left(4ca+2a\right)+\left(2c+1\right)\)

\(A=4ab\left(2c+1\right)+2b\left(2c+1\right)+2a\left(2c+1\right)+\left(2c+1\right)\)

\(A=\left(2c+1\right)\left(4ab+2a+2b+1\right)\)

\(A=\left(2c+1\right)\left[2a\left(2b+1\right)+\left(2b+1\right)\right]\)

\(A=\left(2a+1\right)\left(2b+1\right)\left(2c+1\right)\)

11 tháng 3 2021

Ta có:\(A=8abc+4\left(ab+bc+ca\right)+2\left(a+b+c\right)+1\)

\(=8abc+4ab+4bc+4ca+2a+2b+2c+1\)

\(=\left(8abc+4ab\right)+\left(4bc+2b\right)+\left(4ca+2a\right)+\left(2c+1\right)\)

\(=4ab\left(2c+1\right)+2b\left(2c+1\right)+2a\left(2c+1\right)+\left(2c+1\right)\)

\(=\left(2c+1\right)\left(4ab+2b+2a+1\right)\)

\(=\left(2c+1\right)\left[2b\left(2a+1\right)+\left(2a+1\right)\right]\)

\(=\left(2c+1\right)\left(2b+1\right)\left(2a+1\right)\)

a: =(x+y)^3+z^3-3xy(x+y)-3xyz

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

\(=\left(x+y+z\right)\left(x^2+2xy+y^2-xz-yz+z^2-3xy\right)\)

\(=\left(x+y+z\right)\left(x^2+y^2+z^2-xy-xz-yz\right)\)

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

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

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

c: \(=\left(x^2+x\right)^2+3\left(x^2+x\right)+2-12\)

\(=\left(x^2+x\right)^2+3\left(x^2+x\right)-10\)

=(x^2+x+5)(x^2+x-2)

=(x^2+x+5)(x+2)(x-1)

d: =b^2c+bc^2+ac^2-a^2c-a^2b-ab^2

=b^2c-b^2a+bc^2-a^2b+ac^2-a^2c

=b^2(c-a)+b(c^2-a^2)+ac(c-a)

=(c-a)(b^2+ac)+b(c-a)(c+a)

=(c-a)(b^2+ac+bc+ba)

=(c-a)[b^2+bc+ac+ab]

=(c-a)[b(b+c)+a(b+c)]

=(c-a)(b+c)(b+a)

a: Ta có: \(\left(a^2+b^2-5\right)^2-4\left(ab+2\right)^2\)

\(=\left(a^2+b^2-5-2ab-4\right)\left(a^2+b^2-5+2ab+4\right)\)

\(=\left[\left(a-b\right)^2-9\right]\cdot\left[\left(a+b\right)^2-1\right]\)

\(=\left(a-b-3\right)\left(a-b+3\right)\left(a+b-1\right)\left(a+b+1\right)\)

14 tháng 1 2018

= (abc - ab) + (a - ca) + (b - bc) + (c -1)

= ab.(c -1) - a.(c - 1) - b(c -1) + (c -1)

= (c -1).(ab - a - b  + 1)

Câu 1: A

Câu 21: A

 

1 tháng 11 2021

\(16,A\\ 17,C\\ 18,A\\ 19,C\\ 20,A\\ 21,A\)