On the unit cirlce, the cosine of an angle is negative whenever the angle falls in the interval
.
If you recall your special triangles, this cosine occurs for angles of
and
.
More generally, this occurs for
and
, where
is an integer.
Answer:
Graph # 3
Step-by-step explanation:
-2x + 5y > 15 Let x = 0 solve for y
-2(0) + 5y = 15 change the > to an =
5y = 15
y =3 Point (0, 5) is on the graph
Graph # 3 is correct because the y-intercept is 5
x y
0 3 -2(0) + 5y = 15; 5y = 15
5 5 -2(5) + 5y = 15; -10 + 5y = 15; 5y = 25; y = 5
10 7 -2(10) + 5y = 15; -20 + 5y = 15; 5y = 35; y = 7
The graph > the line is dotted and you will shade above the line
-6 +8x = -38
8x = -32
x = -4
I did this by first adding 6 to both sides to get 8x by itself. I then divided by 8 to get x by itself. I remembered to use the - - + rule (Two negatives make a positive, a positive and a negative make a negative). Hope this helps!
