A formula is an equation that contains at least two variables. Sometimes it
is useful to solve a formula for one of the variables. That is, we write that
variable in terms of the other variables.
The density, d, of an object can be found by dividing its mass, m, by its
Solve this formula for v.
|Multiply both sides of the equation
by v, the denominator of the fraction.
||v Â· d
|Divide both sides by d.
We could also solve for v by cross
To check the solution, substitute
for v in the original equation.
The focal length, f, of a thin lens is related to p, the distance between the
lens and the object, and q, the distance between the lens and the image,
by the formula:
We leave the check to you.
|Multiply each side by fpq, the LCD
of the fractions.
|Cancel common factors.
On the right side of the equation,
factor out f.
|= fq + fp
= f(q + p)
|Divide both sides by (q + p), the
coefficient of f.