3) 5:3=51/2:3.3*x
5*3.3*x=3*5.5
16.5*x=16.5
x=1
4) 0.41/(0.6*x-2.5)=12.3/15
(0.6*x-2.5)*12.3=0.41*15
7.38*x-30.75=6.15
7.38*x=6.15+30.75=36.9
x=36.9/7.38=5
5) (2*x-1)/4.5=2.8/(4*1/5)
(2*x-1)*4,2=4.5*2.8
8.4*x-4.2=12.6
8.4*x=12.6+4.2=16.8
x=16.8/8.4=2
6) 0.25/(4*x+1)=0.3/8.4
(4*x+1)*0.3=0.25*8.4
1.2*x+0.3=2.1
1.2*x=2.1-0.3=1.8
x=1.8/1.2=1.5