Which expression is positive
2 answers:
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Graphs of y = x+- 1 and of y = x - 1 are shown in the figure below.
The intersection of the two graphs is the solution for the two equations.
Answer:
There is no solution.
Explanation:
It is clear that the two lines are parallel and will never intersect.
Note that the equation for a straight line is of the form
y = mx + b
where
m = slope,
b = y-intercept.
y = x + 1 has slope of m=1.
y = x - 1 has slope of m=1.
The two slopes are equal.
Because parallel lines do not intercept, there is no solution.
The intersection of the two graphs is the solution for the two equations.
Answer:
There is no solution.
Explanation:
It is clear that the two lines are parallel and will never intersect.
Note that the equation for a straight line is of the form
y = mx + b
where
m = slope,
b = y-intercept.
y = x + 1 has slope of m=1.
y = x - 1 has slope of m=1.
The two slopes are equal.
Because parallel lines do not intercept, there is no solution.
<h3>Answer: Choice C</h3>
{x | x < -12 or x > -6}
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Explanation:
Let's solve the first inequality for x.
(-2/3)x > 8
-2x > 8*3
-2x > 24
x < 24/(-2)
x < -12
The inequality sign flips when we divide both sides by a negative value.
Let's do the same for the second inequality.
(-2/3)x < 4
-2x < 4*3
-2x < 12
x > 12/(-2)
x > -6
The conclusion of each section is that x < -12 or x > -6 which points us to <u>choice C</u> as the final answer.
Side note: The intervals x < -12 and x > -6 do not overlap in any way. There's a gap between the two pieces. We consider these intervals to be disjoint. The number line graph is below.
9514 1404 393
Answer:
D
Step-by-step explanation:
In the second quadrant, ...
c = 180° -arcsin(24/25) ≈ 106.26°
In the third quadrant, ...
d = 360° -arccos(-3/4) ≈ 221.41°
Then cos(c+d) = cos(327.67°) ≈ 0.84498
This is a positive irrational number, greater than 21/100, so the only reasonable choice is the last one:
_____
Perhaps you want to work this out using the trig identities.
cos(c) = -√(1 -sin(c)²) = -7/25
sin(d) = -√(1 -cos(d)²) = -(√7)/4
Then the desired cosine is ...
cos(c+d) = cos(c)cos(d) -sin(c)sin(d)
cos(c+d) = (-7/25)(-3/4) -(24/25)(-√7/4)
cos(c+d) = (21 +24√7)/100 . . . . matches choice D