The clearest way to approach a linear equation is to graph it.  For any graphable equation, the software first manipulates it into its standard form before graphing; for a linear equation, that form is "y=mx+b" where the slope "m" may then be determined by inspecting the equation (for example, in the equation "y=-2x+4" "-2" is the correct value for "m"). For a parabolic equation, the standard form is y = a(x - h)^2 + k, from which direction (polarity of "a") and axis of symmetry (value of "h"), etc. may be determined by inspection.

Graphing your equation obtains the same equation when using 'Solve' and selecting 'solve for "y"', but graphing the equation clearly identifies that the 'standard form' is solved for.  The slope, 'm' is '4' and the y-intercept, 'b', is '-6'.