Margaret paid $36.00 for 3 team sweatshirts. Which number sentence can she use to find c, the cost of each sweatshirt?

Perform the indicated operation. 8/a - 6/a + 7/a

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.

Asap! i'm not good math and i'm lost.