Question

Determine o valor de X nas proporções
a)8/7=10/x
b)x+4/125=2/25
c)x+3/4=x+9/7
d)x+5/5=3x-15/10
e)x+3/3=20/6

Answer 1

A)

8/7=10/x

8/7 x=10

8x/7=10

8x=10×7

8x=70

x=70/8

x=35/4

B)

(x+4)/(125)=2/25

x+4=2/25×125

x+4=250/25

x+4=10

x=10-4

x=6

C)

(x+3)/(4)=(x+9)/(7)

7(x+3)=4(x+9)

7x+21=4x+36

7x=4x+36−21

7x=4x+15

7x−4x=15

3x=15

x=15/3

x=5

D)

(x+5)/5=(3x-15)/10

x+5/5=3(x-5)/10

1 + x/5= 3(x-5)/10

10+2x=3(x−5)

10+2x=3x−15

10=3x−15−2x

10=x−15

10+15=x

25=x

x=25

E)

(x+3)/3=20/6

1 + x/3 = 20/6

1 + x/3=10/3

x/3=10/3 - 1

x/3=7/3

x=7/3 × 3

x=21/3

x=7