[tex]10\%\:din\:x\:este\:40 \implies\frac{10}{100} \cdot x =40[/tex]
[tex]\implies \frac{1}{10} \cdot x = 40 \,|\cdot10 \implies x= 10\cdot40=400[/tex]
[tex]25\% \:din\: x \: este \: 900 \implies \frac{25}{100}^{(25} \cdot x =900[/tex]
[tex]\implies \frac{1}{4} \cdot x = 900 \,|\cdot 4 \implies x=3600[/tex]
[tex]80\%\:din\:x\:este\:1040 \implies \frac{80}{100} ^{(10}\cdot x = 1040[/tex]
[tex]\implies \frac{8}{10} \cdot x=1040\,|\cdot10 \implies x=\frac{10400}{8} =1300[/tex]
[tex]24\%\:din\:240\:este\:x \implies \frac{24}{100} \cdot240=x[/tex]
[tex]\implies \frac{24\cdot240}{100} ^{(10}=x \implies x=\frac{24\cdot24}{10} =\frac{576}{10} =57,6[/tex]
[tex]15\%\:din\:300\:este\:x \implies \frac{15}{100} \cdot 300 =x[/tex]
[tex]\implies \frac{15\cdot300}{100} ^{(100}=x \implies x=15\cdot3=45[/tex]
