Respuesta :

Answer:

a = 18

Step-by-step explanation:

Slope = (7-6)/(4-8) = -1/4

y-intercept = 7 - (-1/4)(4) = 8

Equation of the line: y = - 1/4x + 8

(Substitute y for 3.5. When y is 3.5, what is x)

3.5 = - 1/4x + 8

3.5 - 8 = - 1/4x

(-4.5) / (- 1/4) = x

x = 18