Can someone help, please? I'm stuck.

Write two subtraction equations that are equivalent to 5 + 12 = 17.

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?

Rewrite the following quadratic functions in intercept or factored form. show your work. y = 9 + 12x + 4x^2