Question

1) Rút gọn đa thức

a) ( x+8)\(^2\) - 2( x+8) ( x-2) + ( x-2)\(^2\)

b) x(x-4) ( x+4) - ( x\(^2\)+ 1) (x\(^2\)-1)

c) 2(x+3y) ( 2x - 3y) - (2x - 1)\(^2\)+ ( 3y-1)\(^2\)

Answer 1

a: \(\left(x+8\right)^2-2\left(x+8\right)\left(x-2\right)+\left(x-2\right)^2\)

\(=\left(x+8-x+2\right)^2=10^2=100\)

b: \(=x\left(x^2-16\right)-\left(x^4-1\right)\)

\(=x^3-16x-x^4+1\)

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

\(=4x^2+6xy-18y^2-4x^2+4x-1+9y^2-6y+1\)

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