Answer:
-2.15
Step-by-step explanation: <em>I was kind of confused on what you asked. If you were asking for </em>0.4-2.55<em>, then that is the answer above.</em>
A single angle is generally not considered to be supplementary. Supplementary angles are angles that equal 180° when they are added together. For example, 70° and 110° are supplementary because they equal 180°.
However, I guess the supplementary angle can be the angle that must be added to another to total 180°. For example, 80° is the supplementary angle of 100°.
Three tenths is the same as 3/10
the sum of -2 and -28 is -30
3/10 of -30 is the same as the products of the two
3 x -30 / 10 = -90/10 = -9
Your answer is
3(-2 + -28)/10 = -9