Write an equation of a line that passes through the point (4,3) and is perpendicular to the graph of the equation y=−13x+4y

To get a line that is perpendicular, just find the slope and take the negative reciprocal of the slope.  
The slope is -13, so the negative reciprocal is +1/13.
Substittue (4,3) into the equation to find the b value.
3=(1/13)4 + b
b=12/13
y=x/13 + (12/13)

Logical equivalent of the give question is its contrapositive