[tex]a)(x + 1)(x + 2) =x^{2}+2x+x+2 = x^{2}+3x+2[/tex]
[tex]b) (3a + 4)(a-5)=3a^{2}-15a + 4a-20=3a^{2}-11a-20[/tex]
[tex]c) (2t+2)(1-3t) = 2t-6t^{2}+2-6t = -6t^{2} -4t+2[/tex]
[tex]d) (3ab-7)(3-7ab)=9ab-21a^{2}b^{2}-21-49ab=-21a^{2}b^{2}-40ab-21[/tex]
:)
