Unit 4
Linear equations.
Solving an equation step by step, inequalities, rearranging a formula, and two equations in two unknowns.
Before this unit
The unit, lesson by lesson
Lessons
4 lessons · 16 practice questions · about an hour
Solving an equation
An equation as two lines that meet, and solving it step by step by doing the same thing to both sides until x is on its own.
Inequalities
When one side is smaller than the other, how the solution becomes a whole stretch of the x-axis, and why multiplying or dividing by a negative number turns the sign round.
Rearranging a formula
A formula is an equation with several letters. You isolate one of them with the same steps, and get a new formula that answers the opposite question.
Two equations in two unknowns
Two lines, one point that satisfies both, and two ways to find it without the board, substitution and adding the equations. And what happens when the lines are parallel.