Which reason for step 4 completes the proof?

prove: -(a + b) + a = -b

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.

The standard deviation for a set of data is 5.5. the mean is 265. what is the margin of error?

Acompany manufactures three types of cabinets. it makes 110 cabinets each week. in the first week, the sum of the number of type-1 cabinets and twice the number of type-2 cabinets produced was 10 more than the number of type-3 cabinets produced. the next week, the number of type-1 cabinets produced was three times more than in the first week, no type-2 cabinets were produced, and the number of type-3 cabinets produced was the same as in the previous week.