What is the location of the vertex of the parabola defined by f(x) = −x2 + 8x − 21 and in what direction does the parabola open?

41/17 as a decimal rounded to the nearest hundredth

A33 gram sample of a substance that's used to detect explosives has a k-value of 0.1473. n = noekt no = initial mass (at time t = 0) n = mass at time t k = a positive constant that depends on the substance itself and on the units used to measure time t = time, in days

Ab based on the given diagram, if m_1 = 60° then m 2 = 30 60 90 180