Question

calcule o valor de X nas proporções
X /3 =21/7

2/x=8/(x+4)

Answer 1

x/3= 21/7
x/3= 3
x= 9

2/x= 8/(x+4)
2= (8/(x+4))•x
2=8x/(x^2+4x)
2(x^2+4x)= 8x
2x^2+8x=8x
2x^2=0
x=0