Final answer:
The number that satisfies the equation a=5 is c. 5. Other options provided do not satisfy the equation. Insignificant figures, non-zero numbers are counted, whereas leading zeros are not. Option C is correct.
Step-by-step explanation:
The equation given is a=5. This means that the value of 'a' that satisfies the equation must equal 5. To answer the question, we match the options provided with the equation. The number that satisfies the equation is c. 5. Therefore, none of the other options (0, 2, or 7) are correct since they do not equal 5.
Regarding the statement 'If /1 = 5 A and 13 = -2 A, 12 will be equal to', we cannot provide a definitive answer because the symbols /1, 13, and 12 are not defined in a mathematical context, and it's unclear how they relate to the variable 'a'. If there is a typo, please provide the correct equation for further assistance.
When discussing significant figures, the number of significant figures depends on the rules of measurement. For example, in the number 5.87, there are three significant figures. The rule here is that all non-zero numbers are significant (Rule 1). When looking at a number like 0.031, there are two significant figures. The leading zeros are not counted as significant (Rule 2), but the 3 and 1 are significant as they are non-zero digits.