Resposta:
a)(x+7).(x-4)
[tex]x^{2} -4x+7x-28\\x^{2} +3x-28[/tex]
b)(3x+4).(2x+1)
[tex]6x^{2} +3x+8x+4\\6x^{2} +11x+4[/tex]
c)(x-4y).(x-y)
[tex]x^{2} -xy-4xy+4y^{2}\\x^{2} -5xy+4y^{2}[/tex]
d) (3x²- 4x - 3) . (x + 1)
[tex]3x^{3}+3x^{2} -4x^{2} -4x-3x-3\\ 3x^{3} -x^{2} -7x-3[/tex]
e) (x² - x - 1) . (x - 3)
[tex]x^{3} -3x^{2} -x^{2} +3x-x+3\\x^{3}-4x^{2} +2x+3[/tex]
