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The equation k= 3x^2 - x^3 is satisfied by one value for x between -2 and 4. what can be said about the value of k?

- Nats
**Posts:**18**Joined:**Mon Aug 19, 2013 11:14 am

Nats wrote:The equation k= 3x^2 - x^3 is satisfied by one value for x between -2 and 4. what can be said about the value of k?

think of this like 2 functions: Y1 = 3x^2 - x^3 & Y2 = k. look at the graph of Y1 and think abt where you'd only get ONE number for x going with a number for y = Y2 = k. (but you probably need calculus for this, too????)

- buddy
**Posts:**115**Joined:**Sun Feb 22, 2009 10:05 pm

buddy wrote:Nats wrote:The equation k= 3x^2 - x^3 is satisfied by one value for x between -2 and 4. what can be said about the value of k?

think of this like 2 functions: Y1 = 3x^2 - x^3 & Y2 = k. look at the graph of Y1 and think abt where you'd only get ONE number for x going with a number for y = Y2 = k. (but you probably need calculus for this, too????)

x = -2 -1 0 1 2 3 4

y = 20 -2 0 2 4 0 -16

still dont understand the value of k

- Nats
**Posts:**18**Joined:**Mon Aug 19, 2013 11:14 am

Nats wrote:x = -2 -1 0 1 2 3 4

y = 20 -2 0 2 4 0 -16

still dont understand the value of k

what did you get for a graph? what heights have 2+ x's that give that height? what heights match only 1 x? copy off the picture.

- buddy
**Posts:**115**Joined:**Sun Feb 22, 2009 10:05 pm

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