If a is not equal to b and 1/x + 1/a = 1/b then x=

ab / (a-b) = x

Step-by-step explanation:

1/x + 1/a = 1/b

Multiply by axb to get rid of fractions

axb (1/x + 1/a) = 1/b * axb

ab + bx = ax

Subtract bx from each side

ab+bx - bx = ax-bx

ab = ax-bx

Factor out x

ab = x (a-b)

Divide each side by (a-b)

ab / (a-b) = x (a-b) / (a-b)

ab / (a-b) = x