Odpowiedź:
1.
[tex](2a-3)(4x-7)=4ax-14a-12x+21[/tex]
2.
[tex](2x+1)(-3x+6+a)=-6x^{2} +12x+2xa-3x+6+a=\\ =-6x^{2} +9x+2xa+a+6[/tex]
3.
[tex](-a+3b)(2a-5b)=-2a^{2} +5ab+6ab-15b^{2} =\\ =-2a^{2} -15b^{2} +11ab[/tex]
4.
[tex](2a-3)(-5a-4)=-10a^{2} -8a+15a+12=\\ =-10a^{2} +7a+12[/tex]
5.
[tex](3a+2b-1)(-a-2b)=-3a^{2} -6ab-2ab-4b^{2} +a+2b=\\ =-3a^{2} -4b^{2} -8ab+a+2b[/tex]
6.
[tex](a-3b)(8b-5a)=8ab-5a^{2} -24b^{2} +15ab=\\ =-5a^{2} -24b^{2} -8ab+15a[/tex]
7.
[tex](5a-4b)(3b-2a)=15ab-10a^{2} -12b^{2} +8ab=\\ =-10a^{2} -12b^{2} +23ab[/tex]
8.
[tex](4a^{2} -1)(a^{2} +5)=4a^{4} +20a^{2} -a^{2} -5=\\ =4a^{4} +19a^{2} -5[/tex]
9.
[tex](5ab^{2} +4b^{3} )(3ab^{3} -4a^{2} )=15a^{2} b^{5} -20a^{3} b^{2} +12ab^{6} -16a^{2} b^{3}[/tex]
