m∠ABC=(6x+8)° and m∠DEF=(12x-8)°. If ∠ABC and ∠DEF are supplementary, what is the measure of each angle? I CAN'T ANSWER THIS QUESTION FOR THE LIFE OF ME!

Answer 1

you forgot what it means for two angles to be supplementary: their sum is 180°

So, to find x, set
(6x+8) + (12x-8) = 180
Now that you know that x=10, you can find the angles.