Respuesta :

Answer:

2a

Step-by-step explanation:

using distance formula:

√(x₂-x₁)² + (y₂-y₁)²

putting values,

√{a-(a)}² + {b-b}² = √ {a+a}² + 0²

= √(2a)² = √4a² = 2a

Hope this helps:)