Is this a function why or why not?

Solve the system of equations. y= 2x y= x^2 - 15

In two or more complete sentences, formulate how to use technology to calculate the appropriate regression model for the given data. you are not required to find the model, just choose the appropriate regression and explain how to use the technology. (-5,,2.,0.8), (0,-0.5), (2,-1.3), (3,-0.8), (5,2)

What is the answer to this question? i'm a bit stumped. also how do i do it? 5(x - 4) = 2(x + 5)