Kira wants to graph y=-3(x + 1)(x - 3). They think that it will be a downward-opening parabola. They think that it has x- intercepts at (1, 0)
and (-3, 0). They think that the axis of symmetry, or x-coordinate of the
vertex, will be halfway between 1 and -3, or -1. They substitute that into
their function, and get a y-coordinate of O. So, they graph their work, and
get what is shown. Explain whether you agree or disagree with Kira's work,
and if you disagree, what you think should be done differently. Answer
specifically about x-intercepts, the midpoint and axis of symmetry, and
vertex of the graph.

-3

step-by-step explanation:

a drawing really does here:

so i draw the horizontal line y=2 and the vertical line x=-2 at this intersection i put b (this is where my right angle is going to be).   so point b is at (-2,2).   point a is 5 units long and is also on y=2 so this point has to be (3,2) or (-7,2) -doesn't matter i will go with (3,2).

now we know c is at (-2,y) we don't know the y yet bet we know that c is on x=-2.

we have the area of the triangle is .5bh=12.5

we know the base length is 5 (ab)

we have the height is (2-y) if you look at your

plug in

.5(5)(2-y)=12.5

solve for y to get the y-coordinate for c

2.5(2-y)=12.5

divide both sides by 2.5 giving:

2-y=5

now subtract 2 on both sides

-y=3

y=-3

answer: cos [   arcsin (3/5) - arccos (1/2) ] =

step-by-step explanation: × = 3/5 = 0.6--> x = 36.87 and x = 180 - 36.87 = 143.13 deg

cos y = 1/2 --> y = +- 60 deg a. cos (x - y) = cos (143.13 - 60) = cos 83,13  

=

0.12

b. cos (36.87 - 60) = cos (-23.23) = 0.92