What is the value of x?

a)20
b)35
c)60
d)70

For this case we have to define by opposite angles the vertex that:

Subtracting 3x on both sides of the equation:

Subtracting 40 from both sides of the equation:

Dividing between -2 on both sides of the equation:

So, we have that

x =±sqrt(1/3)

step-by-step explanation:

x+4/6x=1/x

multiply each side by 6x to get rid of the fractions

6x*(x+4/6x)=1/x*6x

distribute

6x^2 +4 = 6

subtract 4 from each side

6x^2 +4-4 = 6-4

6x^2 =2

divide by 6

6x^2/6 = 2/6

x^2 = 1/3

take the square root of each side

sqrt(x^2) = ±sqrt(1/3)

x =±sqrt(1/3)