Solving For An Unknown Variable In An Equation - HP -32S Owner's Manual

Solving for an Unknown
Variable in an Equation
7
The SOLVE operation can solve for any one variable in an equation.
For instance, take the function
x2 - 3y.
This function can be set equal to zero to create the equation:
x2 - 3y = 0.*
If you know the value of y in this equation, then SOLVE can solve for
the unknown x. If you know the value of x, then SOLVE can solve for
the unknown y. This works for 'word problems'' just as well:
Markup x Cost = Price
Markup x Cost — Price = 0.
If you know any two of these variables, then SOLVE can calculate the
value of the third.
When the equation has only one variable, or when known values are
supplied for all the variables except one, then to solve for x is to find
the root(s) of the equation. A root of an equation occurs where the
graph of the function crosses the x-axis, because at that point the
value of the function equals zero.
*Actually, you can set the function equal to any real value, such as x2 — y =» 10. This can
then be expressed as x2 — y — 10 ° 0 to use SOLVE.
110 7: Solving for an Unknown Variable in an Equation