I believe the answer is the second one {starts with (2,-1)}.
To be considered a function, the input which is the x value can only have one output which is the y value. The others have at least one input with multiple outputs.
Problem 7
This triangle is an equilateral triangle. All sides are the same length (some unknown number which we don't care about). All angles are the same measure each 60 degrees. Set this expression equal to 60 and solve for x
25x - 15 = 60
25x - 15+15 = 60+15 ... add 15 to both sides
25x = 75
25x/25 = 75/25 .... divide both sides by 25
x = 3 which is the answer we want
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Problem 8
For this problem, I've decided to break up the work into separate image files to show how I did the steps. Otherwise, it might be really cluttered to have everything typed here on the same page.
To get the coordinates of point E, check out the image labeled "figure 1". For point G, look at "figure 2".
For proof that EG is parallel to BC, look at "figure 3"
For proof that segment EG is half the length of segment BC, look at "figure 4"
Finally, I've drawn on the diagram to visually show what it all looks like as a summary in "figure 5"
Answer: y-(-6)=1/5(X-(-4))
Step-by-step explanation:
to put together a point slope expresion the equation would be y-y1=m(x-x1)
y1 and x1 being the points on the line and (m) being the slope
Answer: 
Step-by-step explanation:
Given
James takes off from Cooma and flies 452 km to south
after that he travels
East of North to reach east of Cooma
Suppose he is
from Cooma
Form the figure, it can be written

Thus, James is
east to initial position.
Answer:
A.
Step-by-step explanation:
A quadratic function may only intercept the y-axis once. This is because the definition of a y-intercept tells us that it is the point where x = 0. If there are multiple points where x = 0, then the expression cannot be a function. As such, a quadratic function can only have one.
Choice B contradicts the previous statement.
Choice C is wrong because the x-intercept is the zero of the function. This is because at a given x-coordinate that touches the x-axis, the y-coordinate will be 'zero'.
Choice D is wrong because the y-intercept is where x = 0.
I hope this helps!