The difference between three times the measurement of the complement of an angle and the measurement of the supplement of that angle is 20 degrees. what is the measurement of that angle?

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