[tex]\underline{3{,}5\,b}-\underline{\underline{2{,}4\,c}}-\underline{\underline{0{,}6\,c}}-\underline{0{,}5\,b}=(3{,}5-0{,}5)\,b+(-2{,}4-0{,}6)\,c=3\,b-3\,c\\\\\\ (4a-7b)-(2a+3b)=\underline{4a}-\underline{\underline{7b}}-\underline{2a}-\underline{\underline{3b}}=(4-2)a+(-7-3)b=2a-10b\\\\\\-2x(x-5)-3(x^2+3x)=-\underline{2x^2}+\underline{\underline{10x}}-\underline{3x^2}-\underline{\underline{9x}}=\\\\{}\qquad\qquad\qquad\qquad \qquad \qquad \qquad =(-2-3)x^2+(10-9)x=-5x^2+x[/tex]
[tex]-2x(8-x)-5(x^2+3x)=-\underline{16x}+\underline{\underline{2x^2}}-\underline{\underline{5x^2}} -\underline{15x}=\\\\{}\qquad\qquad\qquad\qquad \qquad \qquad \quad =(-16-15)x+(2-5)x^2=-31x-3x^2[/tex]
