Bonjour,
1)
[tex]A=\dfrac{2}{3}\times \dfrac{3}{4}+\dfrac{5}{6}-\dfrac{1}{5}\\\\A=\dfrac{1}{2}+\dfrac{5}{6}-\dfrac{1}{5}\\ \\A=\dfrac{3*5+5*5-1*6}{6*5}\\\\A=\dfrac{34}{30}=\dfrac{16}{15}[/tex]
[tex]B=\dfrac{2*4+3*3}{3*4}\times \dfrac{2*3}{3*3+4*2}\\\B=\dfrac{17}{12}\times \dfrac{6}{17}\\\\B=\dfrac{6}{12}=\dfrac{1}{2}[/tex]
2)
[tex]4(x-5)+3(2x+1)=4x-20+6x+3=10x-17\\\\2(3x-5)-2(x-3)=6x-10-2x+6=4x-4\\\\10x-17=4x-4<=>6x=17-4=13\\\\<=>x=\dfrac{13}{6}[/tex]
[tex](x-5)(x+3)=0\\ \\<=> x-5 = 0 \ ou \ x+3=0\\ \\<=> x = 5 \ ou \ x=-3[/tex]
Merci
