Proportional Relationship
Checker

Proportional Equation Checker

Check whether an equation represents a proportional relationship and identify the constant.

y = kx (proportional) vs y = kx + b (not proportional)

The presence of any constant term b breaks proportionality

Enter any equation to check if it represents a proportional relationship

How to use this checker

Enter an equation. The checker tests whether it can be written as y = kx (no added constant).

What this means in math class

The equation test is the fastest: if it's y = kx with no +b, it's proportional. If there's a +b, it's not.

Worked examples

Example 1: Proportional equation

y = 5x

  1. Step 1:Check form: y = kx
  2. Step 2:k = 5, no added constant
Answer: ✅ y = 5x IS proportional (k = 5)

Example 2: Non-proportional equation

y = 3x + 2

  1. Step 1:Check form: y = kx + b
  2. Step 2:b = 2 is present
Answer: ❌ y = 3x + 2 is NOT proportional

Example 3: Fractional constant

y = (2/3)x

  1. Step 1:Check form: y = kx
  2. Step 2:k = 2/3, no added constant
Answer: ✅ y = (2/3)x IS proportional (k = 2/3)

Frequently asked questions

What makes an equation proportional?

It must be writable as y = kx with no constant added or subtracted.

Is y = x proportional?

Yes. The coefficient is 1: y = 1x.

Is y = -4x proportional?

Yes. k can be negative. y = -4x is proportional.

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