The equation of a parabola is given. y = -5/8 x^2 - 3x + 4 what is the equation of the directrix of the parabola?

Which equation shows y= 3 4 x− 5 2 in standard form? a 4x−3y=10 b 3x−4y=10 c 3x−4y=−10 d 4x−3y=−10

Acell phone company offers two plans to its subscribers. at the time new subscribers sign up, they are asked to provide some demographic information. the mean yearly income for a sample of 40 subscribers to plan a is $45,000 with a standard deviation of $9,200. for a sample of 25 subscribers to plan b, the mean income is $64,300 with a standard deviation of $7,100. at the 0.025 significance level, is it reasonable to conclude the mean income of those selecting plan b is larger? assume unequal population standard deviations. hint: for the calculations, assume the plan a as the first sample. what is the decision rule? (negative amount should be indicated by a minus sign. round your answer to 3 decimal places.) compute the value of the test statistic. (negative amount should be indicated by a minus sign. round your answer to 2 decimal places.) what is your decision regarding h0 ? reject h0 fail to reject h0 compute the p-value. less than 0.01 between 0.01 and 0.025 between 0.025 and 0.05 between 0.05 and 0.10 greater than 0.10

Suppose you have 10 skittles. 5 green and 5 red. you choose 4 without looking. what is the probability that all 4 skittles will be green?