3)x∈z 7/x-3⇒
7=x-3⇒
x=-10
2)
a)x-1/2=-11/4⇒x-1/2=-3/4⇒2x-1/2=-3/4⇒-6=8x-4⇒-8x=6-4⇒-8x=2⇒x=-8/2⇒x=-4
b)3x-2=6⇒3x=2+6⇒3x=8⇒x=8/3
c)3(2x-1)=73/4⇒6x-3=21/28⇒28(6x-3)=21⇒
168x-84=21⇒168x=84+21⇒168x=105
x=105/168
5)51/2×(-2/11)+(-1/3)÷(-7/9)=
11/2×(-2/11)+(-1/3)×(9/7)=
(-1)+(-3/7)=
-7-3/7=-10/7
succes
