Easy slope equation just don’t remember

Given this information, which expression must represent the value of b?

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.

Simplify 15(x - 4)(x -1)-3(x + 4)(x - 1) with steps