How do write seven-hundredths in standard form

Marco has $38.43 dollars in his checking account. his checking account is linked to his amazon music account so he can buy music. the songs he purchases cost $1.29. part 1: write an expression to describe the amount of money in his checking account in relationship to the number of songs he purchases. part 2: describe what the variable represents in this situation.

What is the prime factorization of 23 ?me with this question

We just started the introduction into circles and i have no idea how to do this.