=> B= (2x+1)(2x+1-2x+1)
=> B=(2x+1).2 =>B=4x+2
\(\left(2x+1\right)^2-\left(2x+1\right)\left(2x-1\right)\)
\(=4x^2+4x+1-4x^2+1=4x+2=2\left(x+2\right)\)
chúc bn hc tốt ^^
Ta có B=(2x+1)2-(2x+1)(2x-1)
=>B=4x^2+1-4x^2-2x+2x+1
=>B=(4x^2-4x^2)+(-2x+2x)+(1+1)
=>B=2