Question 21025
Initial problem:
a = lw

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

Add '-1lw' to each side of the equation.
a + -1lw = lw + -1lw

Combine like terms: lw + -1lw = 0
a + -1lw = 0

Add '-1a' to each side of the equation.
a + -1a + -1lw = 0 + -1a

Combine like terms: a + -1a = 0
0 + -1lw = 0 + -1a
-1lw = 0 + -1a
Remove the zero:
-1lw = -1a

Divide each side by '-1l'.
w = al-1

Simplifying
w = al-1

Hope this is what you needed.