a)(2x+3) × 4/3 = 100/9
2x+3=100/9 × 3/4
2x+3=25/3
2x=25/3 - 3
6x=25-9
6x=16
x=16/6=8/3=2,(6)
b)(x+1) × 4/7 = 4/7
x+1=4/7 : 4/7
x+1=1 =>x=0
c)4,75=475/100=95/20=19/4
0,35=35/100=7/20
0,5=5/10=1/2
(x + 1/4 + 1/2) × 4/19 = 7/20 + 1/2 × 1/10
(4x+3)/4 × 19/4 = 8/20
(4x+3)/4 = 8/20 × 19/4
(4x+3)/4 = 19/10 |×2
(4x+3)/2 = 19/5
4x+3=19/5 × 2
4x+3=38/5
20x+15=38
20x=23
x=23/20=1,15