.90=ln(y)

Solution for .90=ln(y) equation:

Simplifying
0.90 = ln(y)

Multiply ln * y
0.90 = lny

Solving
0.90 = lny

Solving for variable 'l'.

Move all terms containing l to the left, all other terms to the right.

Add '-1lny' to each side of the equation.
0.90 + -1lny = lny + -1lny

Combine like terms: lny + -1lny = 0
0.90 + -1lny = 0

Add '-0.90' to each side of the equation.
0.90 + -0.90 + -1lny = 0 + -0.90

Combine like terms: 0.90 + -0.90 = 0.00
0.00 + -1lny = 0 + -0.90
-1lny = 0 + -0.90

Combine like terms: 0 + -0.90 = -0.9
-1lny = -0.9

Divide each side by '-1ny'.
l = 0.9n-1y-1

Simplifying
l = 0.9n-1y-1