Question

Anyone knows how to do 4a)

Answer 1

Sure.  Brainly just made me an Ace.

Let's plug in 1/x as the independent and xy as the dependent in point slope form:

$xy = m (\frac 1 x) + b = \frac m x + b$

We have two points (1/x,xy)=(-4,-2) and (1/x,xy)=(3,5)

That's a slope

$m = \dfrac{5- -2}{3 - -4} = 1$

So a y intercept

5 = 3 + b

b = 2

$xy = \dfrac 1 x + 2 = \dfrac{2x + 1}{x}$

That's easy to solve for y:

$y =\dfrac{2x+1}{x^2}$

When x=1 that's

$y = \dfrac{2+1}{1} = 3$

Answer 2

 just use the slope form and replace digits with x and y