Algebra

"Is" or "Was" = the equal sign. This is the most reliable way to turn confusing word problems into solvable equations.

Check R^2 in any table regression. It must equal 1 for the equation to be a perfect fit.

Constants stay the same while variables vary. Use lists in Desmos to prove your constant is valid for all x.

Unit cancellation: always write out your fractions to ensure units actually cancel before doing the math.

Intersections ARE solutions. The number of times graphs cross is exactly the number of solutions.

Split to count: always split a single equation into two lines if you are counting intersections.

Regression is limited: only use it for constants. For multiple intersection points, graphing is mandatory.

"Is" or "Was" = equals. The most reliable way to turn complex word problems into solvable systems.

Always zoom in on boundary lines to check for dashes. Do not trust your eyes from a distance.

Solid line means equals is allowed. Dashed line means no equals allowed.

The double-shaded area is the only valid region for a system of inequalities.

For triangle side questions, the third side must be greater than the difference and less than the sum of the other two sides.