How can you obtain a result of -1.02x + 2.29y using the two expressions below

Add the two expressions 3.8b - 7 and 2.9b + 9 enter your answer in simplified form

Write the rational number in lowest terms 99/-15

Tim's phone service charges $26.39 plus an additional $0.21 for each text message sent per month. if tim's phone bill was $31.64, which equation could be used to find how many text messages, x, tim sent last month?