How to Plot/Graph/Show a system of linear equations

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Disclaimer: I'm new to Sage Math and Linear equations.

Background: Google will plot/graph this search: "plot 3x+4y"

Questions:

1. In Sage Math, how can I show similar output as Google?

2. Is there a better way, in 2D or 3D, to plot the following? 3x+4y=2.5 AND 5x-4y=25.5 ?

   x, y = var('x,y')
   a=3*x+4*y==2.5
   b=5*x-4*y==25.5
   p1=implicit_plot(a, (x,-2,5), (y,-4,4), axes="true", aspect_ratio=1)
   p2=implicit_plot(b, (x,-2,5), (y,-4,4), axes="true", aspect_ratio=1)
   show(p1+p2)