Which of the following graphs shows a line with a slope of zero? (pic above)

(hurry! ) which expression is equivalent to the following complex fraction?

Ageologist had two rocks on a scale that weighed 4.6 kilograms together.rock a was 0.5 of the total weight.how much did rock a weigh?

Weekly wages at a certain factory are normally distributed with a mean of $400 and a standard deviation of $50. find the probability that a worker selected at random makes between $450 and $500