Lesson Text: Linear equations help us find unknown numbers. To form an equation from a word problem, pick a letter (like (x)) to represent the unknown number. Look for keywords: “sum” means add ((+)), “difference” means subtract ((-)), and “times” means multiply ((times )).
Worked Example: Question: A parent bought (x) exercise books. A textbook costs three times as much as an exercise book. The total cost of one textbook and one exercise book is KES 400. Form an equation. Step 1: Let the exercise book cost = (x) Step 2: The textbook costs three times more = (3x) Step 3: Add them together for the total: (x + 3x = 400 rightarrow 4x = 400)