Question

  giải giúp vs ạ

Answer 1

Bài 1:

\(a.2x^2y\left(x+y-1\right)\\ =2x^2y\cdot x+2x^2y\cdot y-2x^2y\\ =2x^3y+2x^2y^2-2x^2y\\ b.\left(x+2\right)\left(x-2\right)-x^2\\ =x^2-4-x^2\\ =-4\)

Bài 2: 

\(a.8x^2-4x\left(2x+1\right)=-16\\ \Leftrightarrow8x^2-8x^2-4x=-16\\ \Leftrightarrow-4x=-16\\ \Leftrightarrow x=\dfrac{-16}{-4}=4\\ b.\left(x+3\right)\left(x-2\right)-x^2=5\\ \Leftrightarrow x^2+3x-2x-6-x^2=5\\ \Leftrightarrow x-6=5\\ \Leftrightarrow x=6+5=11\)