Estoy haciendo Numeros reales e irracionales y hay un ejercicio que dice “expressa como fracción aquellos que sean posibles” 4,2= 42-4/9= 38/9 mi pregunta es de donde sale el 9 no lo entiendo.

a complex number is a number that can be expressed in the form a + bi, where a and b are real numbers, and i is a solution of the equation x2 = −1. because no real number satisfies this equation, i is called an imaginary number. has no real solution, since the square of a real number cannot be negative.

i believe that the answer is

b. y-1=-2(x-4)

hope this !