Answer:
Step-by-step explanation:
If you're looking for what the half angle of the tangent of theta is, I'm a bit confused as to why you think the angle in the 4th quadrant, x, is relevant. But maybe you don't know it isn't and it's a "trick" to throw you off. Hmm...
Anyways, the half angle identity for tangent is

There are actually 3 identities for the tangent of a half angle, but this one works just as well as either of the others do, so I'm going with this one.
If theta is in QIII, the value of -4 goes along the x axis and the hypotenuse is 5. That makes the missing side, by Pythagorean's Theorem, -3. Filling in our formula:
which simplifies a bit to
and a bit more to

Bring up the lower fraction and flip it to divide to get
which of course simplifies to
-3. Choice A.
Answer:
See attachment
Step-by-step explanation:
We want to graph the system
2x+y=8
-x+2y=6
Let us rewrite the lines in slope intercept form:
y=-2x+8

The first line has a slope of -2 and a y-intercept of 8
The second line has a slope of 1/2 and a y-intercept of 3
We can no graph the lines as shown in the attachment.
Lets say that the two unknown integers are

and

.
We know the following things about

and

:


And, we want to find

.
To solve this, we'll use the expansion of the squared of the sum of any two inegers; this is expressed as:

So, given what we know about the unknown integers, the previous can be written as:

We can easily solve for

:
The answer is 168.
Another approach to solve the problem is, from the two starting equations, compute the values of

and

, which are 12 and 14, and directly compute their product; however, the approach described is more elegant.
Answer:
s = 130 degrees
Step-by-step explanation:
decagon has a 1,440 degrees interior angles
equation: 1,440 = s + 1310
to find s, add all the known angles
⇒ s + 150 + 170 + 160 + 130 +120 + 160 + 105 + 160 +155
⇒ s + 1,310
equation:
s + 1310 = 1440
subtract each side by 1310
⇒ s + 1310 - 1310 = 1440 - 1310
⇒ s = 130