Question

sd hằng đẳng thức để thực hiện phép tính

(2x-1-3y)(2x+1+3y)

Answer 1

\(\left(2x-1-3y\right)\left(2x+1+3y\right)=\left(2x\right)^2-\left(1+3y\right)^2=4x^2-1-6y-9y^2\)

Answer 2

\(\left[2x-\left(1+3y\right)\right]\left(2x+3y+1\right)=4x^2-\left(3y+1\right)^2=4x^2-9y^2-6y-1\)

Answer 3

\(\left(2x-\left(1+3y\right)\right)\left(2x+\left(1+3y\right)\right)\)

\(\left(2x\right)^2-\left(1+3y\right)^2\)

\(4x^2-1-6y-9y^2\)

\(=4x^2-9y^2-6y-1\)