• ${\displaystyle \frac{1}{2}}x\cdot (4x-3)={\displaystyle \frac{1}{2}}x\cdot 4x+{\displaystyle \frac{1}{2}}x\cdot (-3)={\displaystyle \frac{4}{2}}{x}^2-{\displaystyle \frac{3}{2}}x=2x^2-\mathrm{1,5}x\backslash dfrac\{1\}\{2\}x\backslash cdot\; (4x-3)=\backslash dfrac\{1\}\{2\}x\backslash cdot\; 4x+\backslash dfrac\{1\}\{2\}x\backslash cdot\; (-3)=\backslash dfrac\{4\}\{2\}x^2-\backslash dfrac\{3\}\{2\}x=2x^2-1\{,\}5x$

$(2x-7)\cdot (1-3x)=2x\cdot 1+2x\cdot (-3x)+(-7)\cdot 1+(-7)\cdot (-3x)=2x-6x^2-7+21x=23x-6x^2-7(2x-7)\backslash cdot\; (1-3x)=2x\backslash cdot\; 1+2x\backslash cdot\; (-3x)+(-7)\backslash cdot\; 1+(-7)\backslash cdot\; (-3x)=\; 2x-6x^2-7+21x=23x-6x^2-7$