Algebra

First, let's make some observations. 

Note that all points that are 5 units away from the point (2, 7) froms a circle with radius 5 and center (2, 7). 

The equation for that circle would be $(x-2)^2+(y-7)^2=25$

Combining this with the second equation, we get a system. 

$(x-2)^2+(y-7)^2=25\\ y=5x-28$

We already have a y value in terms of x, so we plug that into the first equation. 

We get

$(x-2)^2+(5x-35)^2=25\\ x^2-4x+4+25x^2-350x+1225=25\\ 13x^{2}-177x+602=0$

Now, we can solve for x. Using the quadratic equation, we get

$x=\frac{-{(-177})\pm \sqrt{{(-177)}^{2}-4\cdot {13}\cdot{602}}}{2\cdot {13}}$

$x=\frac{177\pm 5}{26}$

$x=7\\ x=\frac{86}{13}$

Plugging these values for y, we get 

$\begin{pmatrix}x=7,\:&y=7\\ x=\frac{86}{13},\:&y=\frac{66}{13}\end{pmatrix}$

So our final answer is (7, 7) and (86/13, 66/13)

Thanks! :)