a)x/(x+5)=4/9
4x+20=9x
5x=20
x=4
b)x/(x+11)=-3/11
-3x-33=11x
14x=-33
x=-33/14
c)(4+x)/x=9/2
8+2x=9x
7x=8
x=8/7
d)x/5=(-x+6)/(-7)
-5x+30=-7x
2x=-30
x=-15
e|)8/x=15/(23+x)
15x=184+8x
7x=184
x=184/7
f)(x+7)/4x=1/1,2
(x+7)/4x=5/6
6x+42=20x
14x=42
7x=21
x=3
g)(14-x)/x=(60-2x)/(14+2x)
(14-x)/x=(30-x)/(7+x)
30x-x²=98-7x+14x-x²
30x=98+7x
23x=98
x=98/23
h)2x/(7+2x)=(4x+1)/(4x+2,5)
8x²+5x=28x+8x²+7+2x
5x=30x+7
25x=-7
x=-7/25
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i)x4/4x=4/7
(10x+4)/(40+x)=4/7
160+4x=70x+28
66x=132
x=132/66
x=2