a) \(x^2-4x+3\\ =x^2-x-3x+3\\ =x\left(x-1\right)-3\left(x-1\right)\\ =\left(x-1\right)\left(x-3\right)\)
b) \(x^2+4x-12\\ =x^2+6x-2x-12\\ =x\left(x+6\right)-2\left(x+6\right)\\ =\left(x+6\right)\left(x-2\right)\)
c) \(2x^2-3x-2\\ =2x^2-4x+x-2\\ =2x\left(x-2\right)+\left(x-2\right)\\ =\left(x-2\right)\left(2x+1\right)\)
d) \(2x^3+x-2x^2-1\\ =\left(2x^3-2x^2\right)+\left(x-1\right)\\ =2x^2\left(x-1\right)+\left(x-1\right)\\ =\left(x-1\right)\left(2x^2+1\right)\)
e) \(x^4+2x^2-8\\ =\left(x^4+2x^2+1\right)-9\\ =\left(x^2+1\right)^2-3^2\\ =\left(x^2-2\right)\left(x^2+4\right)\)
f) \(x^2-2xy-3y^2\\ =\left(x^2-2xy+y^2\right)-4y^2\\ =\left(x-y\right)^2-\left(2y\right)^2\\ =\left(x-3y\right)\left(x+y\right)\)
a = \(x^2-x-3x+3\)
=\(\left(x^2-x\right)-\left(3x-3\right)\)
=\(x\left(x-1\right)-3\left(x-1\right)\)
=\(\left(x-1\right)\left(x-3\right)\)
b=\(x^x-2x+4x-12\)
=\(\left(x^2-x\right)+\left(4x-12\right)\)
=\(x\left(x-2\right)+4\left(x-2\right)\)
=\(\left(x-2\right)\left(x+4\right)\)
hơi tắt chút chỉ nhóm 2 số đầu với 2 số cuối thôi
dong đầu mk lm í
