A straight line is also known as a supplementary angle with is equal to 180 degrees.
(this is for the first one) All you have to do is subtract the measure of the known angle from 180 degrees.
180 - 40 = 140
180 - 140 = 40
(second one) 105 plus 75 is going to equal 180 degrees. Now going the vertical way (instead of horizontal, the way the know angles are shown) :
180 - 75 = 105
180 - 105 = 75
I hope this helps. Let me know if this was correct/helpful and/or you need anymore help :)
