Which pair of expressions below are equivalent? a. −4−8 and 4+8 b. −4−8 and −4+8 c. −4−8 and −4−(−8) d. −4−8 and −4+(−8)

In a two-digit number the units' digit is 7 more than the tens' digit. the number with digits reversed is three times as large as the sum of the original number and the two digits. find the number.