Răspuns:
Explicație pas cu pas:
15. 2a-2b+2c=2(a-b+c)
16. 3[tex]x^{3}[/tex]+6[tex]x^{2}[/tex]-12x+24=3([tex]x^{3}[/tex]+2[tex]x^{2}[/tex]-4x+8)
17.4[tex]x^{2}[/tex]+12x+9=[tex]2^{2}[/tex][tex]x^{2}[/tex]+2·2x·3+3²=(2x+3)²
18. 9x²-24xy+16y²=3²x²-2·3x·4y+4²y²=(3x-4y)²
19. [tex]x^{4}[/tex]-81=(x²)²-(3²)²=(x²-3²)(x²+3²)=(x-3)(x+3)(x²+3²)
20. 16[tex]x^{4}[/tex]-1= (4x²)²-1²=(2²x²-1²)(4x²+1)=(2x-1)(2x+1)(4x²+1)
