26. A line has a slope of -3 and contains the point (-2,7). Find an equation of this line.
Ans.
-3=(y-7)/(x-(-2) )
-3×(x+2)=y-7
-3x-6=y-7
3x+y=-6+7→3x+y=1

27. Find a line perpendicular to: 6x-4y=13+y
Ans.
6x-5y=13
5y=-6x+13
y=-6/5 x+13/5
For the perpendicular line,
m_1×m_2=-1
6/5×m_2=-1
m_2=-5/6