Consider the problem of finding the line of symmetry and vertex of the quadratic equation f(x) =x^2-8x+15 what is the error in the solution below?
x^2-8x+15=0
x=-8/2 =-8/2=-4 line of symmetry
8^2-8x+15=0
(-4)^2-8(-4)+15=0
16+32+15=0
y=63
(-4,63) vertex
a.
the solution is correct.
b.
the line of symmetry should have been 4 instead of –4.
c.
the vertex is incorrect; it should have been {–4, 53}.
d.
-4^2 should have been squared as –16 instead of 16.

The first-serve percentage of a tennis player in a match is normally distributed with a standard deviation of 4.3%. if a sample of 15 random matches of the player is taken, the mean first-serve percentage is found to be 26.4%. what is the margin of error of the sample mean? a. 0.086% b. 0.533% c. 1.11% d. 2.22%

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.

Which number produces an irrational number multiplied by 1/3