Answer:
x=3
Step-by-step explanation:
9x+63=100
9x+0=27
9(3)=27
That's the second one,
180 - x = r
Whenever two lines cross we get congruent opposite angles and supplemental adjacent angles, i.e. they add to 180 degrees.
The first one is almost right; we have r+y+z=180 and r+x=180 so x=y+z not quite what was written.
Answer:

Step-by-step explanation:
The question to be solved is the following :
Suppose that a and b are any n-vectors. Show that we can always find a scalar γ so that (a − γb) ⊥ b, and that γ is unique if
. Recall that given two vectors a,b a⊥ b if and only if
where
is the dot product defined in
. Suposse that
. We want to find γ such that
. Given that the dot product can be distributed and that it is linear, the following equation is obtained

Recall that
are both real numbers, so by solving the value of γ, we get that

By construction, this γ is unique if
, since if there was a
such that
, then

Answer:
E. None of these
Step-by-step explanation:
Points: (11, -4), (13, -7)
slope = m = (y2 - y1)/(x2 - x1) = (-7 - (-4))/(13 - 11) = (-7 + 4)/2 = -3/2
y - y1 = m(x - x1)
y - (-4) = (-3/2)(x - 11)
y + 4 = (-3/2)x + 33/2
y + 8/2 = (-3/2)x + 33/2
y = (-3/2)x + 25/2
Answer: E. None of these