First find the slope of the reference line:
2x+4y=-6 subtract 2x from both sides
4y=-2x-6 divide both sides by 4
y=-2x/4-6/4
So the slope of the reference line is -2/4=-1/2
For two lines to be perpendicular, the product of their slopes is negative one. Or you could say that the slopes are negative reciprocals of one another, mathematically perpendicular lines slopes will satisfy:
m1*m2=-1, in this case we have:
-1m/2=-1
-1m=-2
m=2
So the perpendicular line in this case has a slope of 2. The slope intercept form of a line is:
y=mx+b and we found than m=2 so:
y=2x+b, and using the point (2,5) we can solve for b
5=2(2)+b
5=4+b
1=b so the perpendicular line passing through the point (2,5) is:
y=2x+1