If 2x + 3y = 12 and x - y = 1, find the value of x.

**The reasoning** We have two equations with two unknowns — this is a **system of simultaneous equations**. The smartest move? Use **substitution** or **elimination**. From equation 2: x - y = 1, so **x = y + 1** Substitute this into equation 1: 2(y + 1) + 3y = 12 2y + 2 + 3y = 12 5y + 2 = 12 5y = 10 **y = 2** Now find x: x = y + 1 = 2 + 1 = **3** ✓ **Why the wrong options tempt you** - **Option A (1):** You might get this if you rushed and swapped x and y values - **Option B (2):** This is actually the value of y, not x! Classic mix-up under exam pressure - **Option D (4):** Likely from arithmetic errors when expanding 2(y + 1) or combining like terms **Quick takeaway** When solving simultaneous equations, **label your answers clearly** — write "y = 2" and "x = 3" separately so you don't submit the wrong variable's value. Always substitute back to verify: Does 2(3) + 3(2) = 12? Yes! Does 3 - 2 = 1? Yes!