Given y = a(x - h)^2 + k, p = A. a B. 4a C. 1/4a
1 answer:
9514 1404 393
Answer:
C. 1/(4a)
Step-by-step explanation:
We assume you're comparing the vertex form ...
y = a(x -h)^2 +k
to the form used to write the equation in terms of the focal distance p.
y = 1/(4p)(x -h)^2 +k
That comparison tells you ...
a = 1/(4p)
p = 1/(4a) . . . . . . multiply by p/a; matches choice C
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<em>Additional comment</em>
When using plain text to write a rational expression, parentheses are needed around any denominator that has is more than a single constant or variable. The order of operations requires 1/4a to be interpreted as (1/4)a. The value of p is 1/(4a).
When rational expressions are typeset, the fraction bar serves as a grouping symbol identifying the entire denominator:
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Ok so we'll go ahead and solve for y first - we just need to get it alone on one side of the equal sign
Step 1: subtract 2x from each side
2x - 7y - 2x = 19 - 2x
This cancels out the 2x on the left, giving us
-7y = 19 - 2x
Step 2: divide both sides by -7
=
+
This gives us
y = -19/7 + 2x/7
That should be your answer for the first question. Now solving the next parts are easy. All you need to do is plug in x.
When x = -3
y = -19/7 + 2x/7
y = -19/7 + 2(-3)/7
y = -19/7 - 6/7
y = -25/7
When x = 0
y = -19/7 + 2x/7
y = -19/7 + 2(0)/7
y = -19/7
When x = 3
y = -19/7 + 2x/7
y = -19/7 + 2(3)/7
y = -19/7 + 6/7
y = -13/7
Hope that helps! Feel free to ask if I can help with anything else :)