+0  
 
0
380
4
avatar+261 

So I saw this question and I'm not entirely sure how to solve it. Would appreciate help with it.

I drew it so you'll have to assume the lines are straight/smooth. This is all the information you get. The other function on the right is just f(x) but flipped upside down. They both meet each other 35 length units up from the bottom. So halfways(through the 70).

You need to solve for x.

Quazars  Feb 4, 2015

Best Answer 

 #4
avatar+26971 
+10

I get the same as Melody, though my derivation is much longer!

 

quadratic

.

Alan  Feb 5, 2015
 #1
avatar+88871 
+5

Something like this...????

https://www.desmos.com/calculator/w6m9u4lmxs

And x = 75

 

CPhill  Feb 4, 2015
 #2
avatar+261 
0

75 would be the point from the middle line to the top right.

150/2

However x should be less than 75 is how far I got and then got stuck. Is it possible to do this without a graphing calculator?

Also how'd you get the equation for the lines because I'm clueless

the (7/1225)x^2 that is

Quazars  Feb 5, 2015
 #3
avatar+93305 
+10

I am probably interpreting the question incorrectly BUT i don't think the second parabola is relevant.

 

Let the vertex of the concave up parabola be (0,0)

The 2 top points are (-75,70) and (75,70)

The equation is

$$\\x^2=4ay\\
75^2=4a*70\\
5625=280a\\
a\approx20.09\\$$

so

$$\\x^2\approx 4*20.09y\\
x^2\approx 80.36y\\
$Find x when y=35\\
x^2\approx 80.36*35\\
x^2\approx 2812.5\\
x\approx 53$$

 

Maybe I didn't understand where the 75 belonged  

Melody  Feb 5, 2015
 #4
avatar+26971 
+10
Best Answer

I get the same as Melody, though my derivation is much longer!

 

quadratic

.

Alan  Feb 5, 2015

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