An example would be using points
(0,0)(1,2)(7,14)(10,20)
it is a function because each input has only one input.
or
using the vertical line test none of the points are on the same line
The value of a=7 will make the equation true
Answer:

Step-by-step explanation:
The formula of a slope:

We have the points

Substitute:

since by the provided tickmarks WE ≅ ER, and QE ≅ ET, then both triangles are congruent by LL theorem, Leg Leg.
anyhow, since those legs are congruent, their hypotenuses must also be congruents, and we could use the HL theorem as well.