a)16-x²=4²-x²=(4+x)(4-x)

b)x⁴-25=(x²)²-5²=(x²-5)(x²+5)

c)4x²=(2x)²=(2x).(2x)

d)(a+b)²-1=(b+a-1)(b+a+1)

e)(x+y)²-(x-y)²=x²+2xy+y²-x²+2xy-y²=4xy

f)4(x+2y)²-9(2y-x)²=(5x-2y)(10y-x)

g)1-4x+4x²=(2x-1)²

h) 25x²-20xy+4y²=(2y-5x)²

\(\frac{16\cdot17-5}{16\cdot16+5}=\frac{272-5}{256+5}=\frac{267}{261}=\frac{89}{57}\)

100%  là đề sai

hih như lộn chủ đề