Question

Which of the following is not a linear equation?

• A. 3x-2y= y + x
• B. x + y = 1
• C. 1+2x=y-5
• D. 3-y= x2+4

Answer 1

The Correct Option is D

Correct answer: 3 - y = x² + 4 

Explanation:
A linear equation is an equation in which the highest power (degree) of any variable is 1. That means all variables appear to the power of 1 only, and no variable is multiplied by another.

Let’s check each option:

Option 1: 3x - 2y = y + x
Simplifying: 3x - 2y - y - x = 0 → 2x - 3y = 0 → degree = 1 (Linear Equation) ✅

Option 2: x + y = 1 → degree = 1 (Linear Equation) ✅

Option 3: 1 + 2x = y - 5
Simplifying: 2x - y = -6 → degree = 1 (Linear Equation) ✅

Option 4: 3 - y = x² + 4
Simplifying: -y = x² + 1 → y = -x² - 1 → degree = 2 (Not a linear equation) ❌

Since this equation contains x², the highest degree is 2. Hence, it is not a linear equation.