Bonjour,
1) [tex] \frac{4}{5}x+x = 1728 \Rightarrow \frac{9}{5}x=1728 \Rightarrow x = \frac{1728}{\frac{9}{5}} = \frac{5*1728}{9} =960[/tex]
2) [tex] \frac{2}{3}x=988 \Rightarrow x= \frac{988}{ \frac{2}{3}}= \frac{3*988}{2} =1482[/tex]
3) 18+2x = 40+x ⇒ x = 40-18 = 22
4) 12x-3 = 5x+18 ⇒ 7x = 21 ⇒ x = 21/7 = 3
5) [tex]8x- \frac{3}{4} =2x- \frac{1}{4} \Rightarrow 6x= \frac{2}{4}= \frac{1}{2} \Rightarrow x = \frac{ \frac{1}{2}} {6} = \frac{1}{2*6} = \frac{1}{12} [/tex]
6) [tex]\frac{24}{7}x+ \frac{1}{14} = \frac{3}{28} \Rightarrow \frac{24}{7}x = \frac{3}{28}- \frac{2}{28} = \frac{1}{28} \Rightarrow x= \frac{\frac{1}{28}}{\frac{24}{7}}= \frac{1*7}{24*28} = \frac{7}{672} = \frac{1}{96} [/tex]
