Question

aflați numărul x dacă: a) x/9=4/3; b) 8/x=2/7; c) 3/4=x/8; d) 4/6=x/9; e) 5/2=25/x; f) x/72=3/8; g) 42/x=7/8; h)5/7=x/56

Answer 1

a) x/9 = 4/3 => x = (4 x 9)/3 = 12
b) 8/x = 2/7 => x = (8 x 7)/2 = 28
c) 3/4 = x/8 => x = (3 x 8)/4 = 6
d) 4/6 = x/9 => x = (4 x 9)/6 = 6
e) 5/2 = 25/x => x = (25 x 2)/5 = 10
f) x/72 = 3/8 => x = (72 x 3)/8 = 27
g) 42/x = 7/8 => x = (42 x 8)/7 = 48
h) 5/7 = x/56 => x = (5 x 56)/7 = 40

Answer 2

a) x/9=4/3
3x=4·9
3x=36
x=36/3
x=12

b)8/x=2/7
8·7=2x
2x=56
x=56/2
x=28

c)3/4=x/8
3·8=4x
4x=24
x=24/4
x=6

d)4/6=x/9
4·9=6x
6x=36
x=36/6
x=6

e)5/2=25/x
5x=25·2
5x=50
x=50/5
x=10

f)x/72=3/8
8x=72·3
8x=216
x=216/8
x=27

g)42/x=7/8
42·8=7x
7x=336
x=336/7
x=48

h)5/7=x/56
5·56=7x
7x=280
x=40