which of the following expressions correctly uses properties of summation to represents the summation

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

The parabola x = y² - 9 opens: a.)up b.)down c.) right d.)left

The magnitude, m, of an earthquake is defined to be m=log l/s, where i is the intensity of the earthquake (measured by the amplitude of the seismograph wave) and s is the intensity of a “standard” earthquake, which is barely detectable. what is the magnitude of an earthquake that is 1,000 times more intense than a standard earthquake? use a calculator. round your answer to the nearest tenth.