SL 1.8—Technology for equations

A graphing calculator can locate numerical roots, intersections and solutions of systems, but it does not decide which solution is meaningful. Enter the equation in a form the calculator can interpret, set an appropriate domain or window, and record the required precision.

For x² − 5x + 6 = 0, graph y = x² − 5x + 6 or use the solver. The roots are x = 2 and x = 3; substituting either value gives zero, confirming the output.

A missed root can come from a poor window or initial guess, and transformed equations can introduce extraneous solutions. Always check the original equation and state domain restrictions or units.

For a system of up to three linear equations, enter all equations with consistent variable order and use the simultaneous-equation solver; examinations use systems with a unique solution. Example: $x+y=7$ and $2x-y=2$ gives $(x,y)=(3,4)$, verified in both equations. A root or zero of a polynomial is a value making the polynomial equal to zero.