As I understood, you need to write General (or standard) form of linear equation -4x+5y =-7 in slope–intercept form y=mx+b (where "m" is the slope of the line and "b" is the y-intercept, which is the y-coordinate of the location where line crosses the y axis.)
You have to solve given equation for "y".
-4x + 5y = -7
+4x           +4x
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5y = 4x - 7 -------------> 5y/5 = 4x/5 -7/5
                                      y = (4/5)x -7/5   ---------------> m = 4/5   and   b = -7/5