Solve

y=4x-8 meets the x axis at point A 

, In other words Point A intersects the x axis, (Draw the graph and you will find that A=2) or simply solve for it setting y=0 

4x-8=0

4x=8

x=2(Intersection)

 

Second part of the question find the equation of the line with gradient 3 that passes through point A,

Gradient is slope.

y=mx+c

m is the slope

In this equation it is 4x (Slope is 4)

So you want a line that intersect the x axis at the same point (A) at 2. but with slope=3

simply,

y=3x-6