Witam, proszę o pomoc w rozwiązaniu zadań w załączniku (12,13 i 15,16). Daję NAJ!

Zad.12 [latex]a) \ (x+2+y)(z+1)=xz+x+2z+2+yz+y \ \ b) \ (a+b)(7-b+4c)=7a-ab+4ac+7b-b^2+4bc \ \ c) \ (p-2s+5t)(5p-3)=5p^2-3p-10sp-6s+25tp-15t[/latex] Zad. 13 [latex]a) \ (c-1)(b+2)+2bc=bc+2c-b-2+2bc=3bc+2c-b-2 \ \ b) \ (1-b)(b-4)+3b=b-4-b^2-4b+3b=-b^2-4 \ \ c) \ (2a-b)(a-2b) +5a^2=2a^2-4ab-ab+2b^2+5a^2=2b^2-5ab+7a^2 \ \ d) \ (b-4)(b-3)-b(b+3)=b^2-3b-4b+12-b^2-3b=-10b+12 \ \ e) \ -(a-b)-5(a-2)(b+1)=-a+b-5ab-5a+10b+10= \ =-6a+11b-5ab+10 \ \ f) \ x(y+2)+(3x+4-y)(y+4)= \ =xy+2x+3xy+12x+4y+16-y^2-4y=4xy+14x+16-y^2[/latex] Zad. 15 [latex]a) \ (2a-b)(a-7b)(5-c)=(2a^2-14ab-ab+7b^2)(5-c)= \ =10a^2-75ab+35b^2-2a^2c-15abc+7b^2c \ \ b) \ (a-3)(b-1)(c+8)=(ab-3b-a+3)(c+8)= \ =abc-3bc-ac+3c+8ab-24b-8a+24 \ \ c) \ -(a-1)(c-2)(b+3)=(-ac+2a+c-2)(b+3)= \ =-abc+2ab+bc-2b-3ac+6a+3c-6 \ \ d) \ z(y-2)(3x-1)(y-4)=(3xyz-yz-6xz+2z)(y-4)= \ =3xy^2z-y^2z-6xyz+2yz-12xyz+4yz+24xz+8z= \ =3xy^2z-y^2z-18xyz+6yz+24xz+8z[/latex] Zad. 16 [latex]a) \ 2x(x-1)=1+2x^2 \ 2x^2-2x-2x^2=1 \ -2x=1 \ x=-dfrac{1}{2} [/latex] [latex]b) \ 2x(x-1)-x^2=(1+x)x \ 2x^2-2x-x^2-x^2-x=0 \ -3x=0 \ x=0[/latex] [latex]c) \ (1+x)(2-3x)=1,5x(1-2x) \ -3x+2x-3x^2-1,5x+3x^2=-2 \ -2,5x=-2 \ x=dfrac{4}{5}[/latex] [latex]d) \ (0,5x-4)x=0,25(1+2x^2) \ dfrac{1}{2}x^2-4x-dfrac{1}{2}x^2=dfrac{1}{4} \ -4x=dfrac{1}{4} \ x=-dfrac{1}{16}[/latex]