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Solving Linear Equations in One Variable
A linear equation looks like ax + b = c — the goal is to get x alone on one side. Use inverse operations: subtraction cancels addition, division cancels multiplication. Whatever move you make, make it on both sides so the equation stays balanced.
4x = 39 − 19 → 4x = 20
x = 20 ÷ 4 → x = 5
✔ Check: 4(5) + 19 = 20 + 19 = 39 ✓
- Isolate x step by step using inverse operations
- Keep both sides balanced — same move on both
- Always substitute your answer back to check it
Q1. What is 20% of 380?
Q2. Solve for x: 4x + 19 = 39
Inside the Cell — The Unit of Life
Every living thing is built from cells. Prokaryotic cells (bacteria) have no true nucleus, while eukaryotic cells (plants, animals, fungi) keep their DNA inside a nucleus. Inside eukaryotic cells, organelles do specialised jobs — like departments inside a factory.
🏢 Nucleus = the manager's office (holds the instructions / DNA)
⚡ Mitochondria = the power station (makes ATP energy)
🔩 Ribosomes = the assembly line (builds proteins)
🚪 Cell membrane = the security gate (controls what enters & leaves)
- Nucleus stores and protects the cell's DNA
- Mitochondria release energy through respiration
- The cell membrane is selectively permeable
Q1. Which organelle produces most of a cell's energy?
Q2. Which cells lack a true nucleus?
Newton's Three Laws of Motion
1st Law (Inertia): an object keeps doing what it's doing — rest or straight-line motion — unless a force interferes. 2nd Law: force equals mass times acceleration (F = ma). 3rd Law: every action has an equal and opposite reaction.
a = F ÷ m = 10 ÷ 2 → a = 5 m/s²
✔ Double the force → double the acceleration. Double the mass → half the acceleration.
- F = ma connects force, mass and acceleration
- Mass resists acceleration — heavier needs more force
- Action–reaction pairs act on different objects
Q1. A 10 N force acts on a 2 kg cart. What is its acceleration?
Q2. Newton's 3rd law states that…
What's Inside an Atom?
An atom has a tiny nucleus of protons (+) and neutrons (0), surrounded by a cloud of electrons (−). The atomic number = number of protons and defines the element. The mass number = protons + neutrons. Isotopes are atoms of the same element with different neutron numbers.
Carbon-14 → 6 protons, 8 neutrons — still carbon (same protons), just a heavier isotope.
- Protons define the element — change protons, change element
- In a neutral atom: electrons = protons
- Mass number = protons + neutrons
Q1. What determines an element's identity?
Q2. Isotopes of the same element differ in their number of…
The Marketing Mix — the 4 Ps
Every marketing plan balances four levers: Product (what you sell), Price (what it costs), Place (where customers get it) and Promotion (how they hear about it). Change one and the others must follow — a premium product sold cheap in the wrong channel confuses customers.
🛍 Product: leak-proof, 3 colours, 750 ml
💰 Price: mid-range — signals quality without scaring students
📍 Place: online store + local gyms & campus shops
📣 Promotion: student influencers + launch-week discount
- Product must solve a real customer problem
- Price must match perceived value
- Promotion mixes ads, social media, discounts and PR
Q1. Which of the 4 Ps covers distribution channels?
Q2. Cutting the price low to grab market share fast is called…
Variables & Loops
A variable stores a value you can reuse — let for values that change, const for fixed ones. A loop repeats a block of code while a condition holds, saving you from copy-paste and typos.
for (let i = 0; i < 3; i++) { console.log(i * 10); }Prints: 10, 20, 30 — the loop runs with i = 0, then 1, then 2, and stops when i < 3 is false.
- let can be reassigned; const stays fixed
- A loop runs: start → condition check → body → update
- Off-by-one errors: i < 3 stops at 2, i <= 3 stops at 3
Q1. for (let i = 0; i < 3; i++) console.log(i) prints…
Q2. Which keyword declares a variable you can reassign later?
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