For simple interest, just multiply all of them together
note that 2% = 0.02
570(0.02)(4) = 45.6
simple interest is 45.6
oh and if you need the equation, it is p(r)t, or principle x rate x time
hope this helps
You could say “you had 18 t-shirts and bought 12 more and now you have a total of 30 t-shirts”
M = -9 ; solve for m by simplifying both sides of the equation, then isolating the varible
