Question

Câu 8 : Tính nhanh

a) A = 2022^2 - 2021^2

b) B = x(y - x) - y + x, với y - x = 0

Answer 1

\(a,A=2022^2-2021^2\)
\(=\left(2022-2021\right)\left(2022+2021\right)\)
\(=4043\)
\(b,B=x\left(y-x\right)-y+x\) với \(y-x=0\)
\(=x\left(y-x\right)-\left(y-x\right)\)
\(=\left(x-1\right)\left(y-x\right)\)
Thay \(y-x=0\) vào biểu thức ta được:
\(\left(x-1\right).0=0\)

Answer 2

a)

\(2022^2-2021^2\\ =\left(2022-2021\right)\left(2022+2021\right)\\ =1\cdot4043\\ =4043\)

b)

\(x\left(y-x\right)-y+x\\ =x\left(y-x\right)-\left(y-x\right)\\ =\left(y-x\right)\left(x-1\right)\\ =0\cdot\left(x-1\right)\\ =0\)

Answer 3

`a)A=2022^2-2021^2=(2022-2021)(2022+2021)=4043`

`b)B=x(y-x)-y+x=x(y-x)-(y-x)=(y-x)(x-1)`

  Mà `y-x=0`

  `=>B=0(x-1)=0`