Odpowiedź :
[tex]a) \\(2x-3)(5-x)-2x(x+4)=10x-2x^2-15+3x-2x^2-8x=-4x^2+5x-15[/tex]
[tex]b) \\(3a-2b)(5a+4)-2a(b-3a)=15a^2+12a-10ab-8b-2ab+6a^2=21a^2+12a-12ab-8b[/tex]
[tex]c)\\(3m-2n)(5+m-3n)=15m+3m^2-9mn-10n-2mn+6n^2=3m^2+6n^2+15m-10n-11mn[/tex]
[tex]d)\\(\frac12t-2s)(s-4t+2)-(+2) =\frac12st-2t^2+t-2s^2+8st-4s-2=-2s^2-4s+\frac{17}2st+t-2t^2-2[/tex]