So just remember tha tyou can do anything to an equation as long as you do it to both sides (except divide by 0) so
-7.12=-4.8+x
add 4.8 to both sides since -4.8+4.8=0 so it cancels
4.8-7.12=x
simplify
4.80-7.12=-2.32
-2.32=x
the naswer is C
8 because 2 3 5 7 11 13 17 19
Answers:
x intercepts are -10 and 50
the y intercept is 5000
The axis of symmetry is x = 20
The vertex is (20, 9000)
The interval of increase is -infinity < x < 20
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Explanations
The x intercepts are where the graph crosses or touches the x axis. In this case, the locations -10 and 50 are where this happens. The y intercept is 5000 as the graph crosses the y axis at this location.
The axis of symmetry is x = 20 because this vertical line cuts the parabola into two mirror halves; one half reflects over the vertical line to line up with the other half.
The x coordinate of the vertex is always equal to the axis of symmetry. The y coordinate of the vertex is y = 9000 and it is the largest y value possible. The vertex is at (20, 9000)
The interval of increase is the portion of the graph that goes uphill as you read from left to right. This is the interval -infinity < x < 20. Basically we stop at the axis of symmetry because after this point, the graph goes downhill and we have a decreasing interval here.
