Answer:
the ratio of the following x is 3/4
A $20 decrease followed by a $20 increase - original value
A 75% decrease followed by a 50% increase - less than the original value
A 50% increase followed by a 33 1/3% decrease - greater than the original value
A 60% increase followed by a 40% decrease - greater than the original value
A 100% increase followed by a 33 1/3% decrease - greater than the original
Write the vertex form of the equation and find the necessary coefficient to make it work.
.. y = a*(x +3)^2 -2
.. = ax^2 +6ax +9a -2
You require the y-intercept to be 7. So, for x=0, you have
.. 9a -2 = 7
.. 9a = 9
.. a = 1
The equation you seek is
.. y = x^2 +6x +7