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

\(=4x^2-6xy+12xy-18y^2-4x^2+4x-1+9y^2-6y+1\)

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