Phân tích các đa thức sau thành nhân tử:
a) (3x-1)^2 -16
b) (5x-4)^2 49x^2
c) (2x +5)^2 -(x-9)^2
d) (3x+1)^2 - 4(x-2)^2
e) 9(2x+3)^2 -4(x+1)^2
f)4b^2c^2 -(b^2+c^2-a^2)^2
g) (ax+by)^2 -(ay+bx)^2
h) (a^2+b^2-5)^2 -49ab+2)^2
i) (4x^2-3x-18)^2 -(4x^2 +3x)^2
k) 9(x+y-1)^2 4(2x+3y+1)^2
l) -4x^2 +12xy -9y^2+25
m) x^2 -2xy +y^2 -4m^2+4mn-n^2
a)\(\left(3x-1\right)^2-16=\left(3x-1-16\right)\left(3x-1+16\right)\)
\(=\left(3x-17\right)\left(3x+15\right)\)
c)\(\left(2x+5\right)^2-\left(x-9\right)^2=\left(2x+5+x-9\right)\left(2x+5-x+9\right)\)
\(=\left(x-4\right)\left(x+14\right)\)
Aps dungj t/c a2 - b2 = ( a-b)(a+b)