Question

1-Calcule o valor de x nas proporções:
a) x+3/4 =x+9/7
b)x+5/5=3x-5/10
c)x+3/3=20/6

Answer 1

A) x+3/4 = x+9/7
7*(x+3) = 4*(x+9)
7x+21=4x+36
7x-4x = 36-21
3x = 15
x = 15/3 = 5

b) x+5/5 = 3x-5/10
10*(x+5) = 5*(3x-5)
10x+50 = 15x-25
50+25 = 15x-10x
75 = 5x
x = 75/5 = 15

c) x+3/3 = 20/6
20*3 = 6*(x+3)
60 = 6x+18
42 = 6x
x = 42/6 = 7