Question

me ajudem nessa questão por favoor

Answer 1

em todos os casos MULTIPLICA EM CRUZ e resolve
a
x/5 = 21/35
35x = 21 * 5
35x =105
x = 105/35 = 7 ****
b
( 3/4)/(1/5)= 90/x
( 3/4).x  = (1/5) .90
3x/4 = 90/5
3x* 5= 90 * 4
15x = 360
x = 360/15 = 24 ****
c
9/13 = x/26
13x = 9 * 26
13x = 234
x = 234/13 = 18 ***
d
1/7 = ( x - 6)/49
7 * ( x - 6)  = 1 * 49
7x -42 = 49
7x = 49 + 42 
7x = 91
x = 91/7 =13 ***
e
( 2x + 1)/10 =- 21/30
10 * (-21)  = 30 ( 2x + 1)
-210 = 60x + 30
-210 - 30 = 60x
60x = - 240
x = -240/60 = - 4****
f
( 3x + 2)/ ( x+ 3) = - 40/25
25( 3x + 2) = -40( x + 3)
75x + 50  = -40x - 120
75x + 40x = -120 - 50
115x = - 170
x = - 170/115  =- 34/23 ****
g
0,3/x = - 6/9
-6x = 9 * 0.3
-6x = 2,7
6x = - 2,7
x = -2.7/6 = - 0,45  ou  - 45/100  = -9/20 ***
h
0,2/5 = x/200
5x = 0,2 * 200
5x = 40
x = 40/5 = 8 ****