Question

Giúp mình câu e đến k ik

Answer 1

e) \(\left(3x-y\right)\left(3x+y\right)=9x^2-y^2\)

f) \(\left(5x+8y\right)\left(5x-8y\right)=25x^2-64y^2\)

g) \(25x^2-16y^2=\left(5x-4y\right)\left(5x+4y\right)\)

h) \(16x^2-9=\left(4x-3\right)\left(4x+3\right)\)

i) \(\left(x+2y+3\right)^2=x^2+4y^2+9+4xy+6x+12y\)

k) \(\left(2x+3y+4\right)^2=4x^2+9y^2+16+12xy+16x+24y\)

Bài 2: 

a) Ta có: \(\left(3x-2\right)\left(4x-5\right)+\left(2x+3\right)\)

\(=12x^2-15x-8x+10+2x+3\)
\(=12x^2-15x+13\)