supplement means adds to 180
coplememtn means add to 90
if the angle is x then
supplemem of that angle
x+y=180
coplement
x+z=90
difference between
3 times complement
and supplement is 20
3z-y=20
look back
x+y=180
x+z=90
solve for z and y
y=180-x
z=90-x
subsitute
3(90-x)-(180-x)=20
distribute
270-3x-180+x=20
add like terms
90-2x=20
subtract 90 from both sides
-2x=-70
divide both sides by -2
x=35
the angle is 35 degrees
