Bài 1:
a: \(=\left(y-1\right)\left(x-2\right)\left(x+2\right)\)
b: \(=\left(x+1\right)^2-y^2\)
\(=\left(x-y+1\right)\left(x+y+1\right)\)
\(=100\cdot\left(84-15+1\right)=100\cdot70=7000\)
Bài 2:
a: \(\dfrac{A}{B}=\dfrac{x^3+x^2+2x^2+2x+x+1-3}{x+1}=x^2+2x+1-\dfrac{3}{x+1}\)
b: Để A chia hết cho B thì \(x+1\in\left\{1;-1;3;-3\right\}\)
hay \(x\in\left\{0;-2;2;-4\right\}\)
1, 2, 3, 4, 5, 6, 7, 8
C D A D B C B C
a,
\(x^2\left(y-1\right)-4\left(y-1\right)=\left(y-1\right)\left(x^2-4\right)\left(y-1\right)\left(x-2\right)\left(x+2\right)\)
b,
\(x^2+2x+1-y^2=\left(x+1\right)^2-y^2=\left(x+1-y\right)\left(x+1+y\right)\)
thay x =84 và y=15 vào bt trên:
(84+1-15)(84+1+15)=7000
a, \(\left(x^3+3x^2+3x-2\right):\left(x+1\right)=x^2+2x+1\)( dư -1)
b,x=2,x=-2
