Bài 1:
a: \(2x^2y\left(x+y-1\right)\)
\(=2x^2y\cdot x+2x^2y\cdot y-2x^2y\cdot1\)
\(=2x^3y+2x^2y^2-2x^2y\)
b: \(\left(x+2\right)\left(x-2\right)-x^2\)
\(=x^2-2^2-x^2\)
\(=-2^2=-4\)
Bài 2:
a: \(8x^2-4x\left(2x+1\right)=-16\)
=>\(8x^2-8x^2-4x=-16\)
=>-4x=-16
=>x=4
b: \(\left(x+3\right)\left(x-2\right)-x^2=5\)
=>\(x^2-2x+3x-6-x^2=5\)
=>x-6=5
=>x=5+6=11