1,
a, `=15x^5-5x^3+40x^2`
b, `=6x^2+2x-15x-5=6x^2-13x-5`
c, `=-5/3x^2+2x-3`
d, `=1/4x^2-3x+9`
g, `=225x^3+60x^2+240x+64`
2,
a, `=7xy(y-2x+7)`
b, `=5(x+4)(x+2)`
c, `=(4-2x+1)(4+2x-1)=(5-2x)(3+2x)`
d, Chắc bạn nhầm dấu?
`x^2-4x+4-y^2=(x-2)^2-y^2=(x+y-2)(x-2-y)`
g, Sai đề!!