PLZ! PLZ! HELP! Scientific Notation

I would really appreciate it! Thanks!

Ineed me i stuck and i don’t want to get it wrong

Valentina is subtracting from . she finds the lcd to be 15y2. what is valentina's next step?

(c) the diagram shows the first three shapes of a matchsticks arrangement.first shape = 3second shape = 5third shape = 7given m represents the number of matchstick used to arrange the n'th shape.(i) write a formula to represent the relation between m and n. express m as the subjectof the formula.(ii) 19 matchsticks are used to make the p'th shape. find the value of p.