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Tabbiejack
Group Title
What is the value of c such that: x2 + 14x + c, is a perfectsquare trinomial?<o:p></o:p>
A. 7
B. 98
C. 196
D. 49
 one year ago
 one year ago
Tabbiejack Group Title
What is the value of c such that: x2 + 14x + c, is a perfectsquare trinomial?<o:p></o:p> A. 7 B. 98 C. 196 D. 49
 one year ago
 one year ago

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Jhannybean Group TitleBest ResponseYou've already chosen the best response.0
\[x^2+14x+c=0\]
 one year ago

ParthKohli Group TitleBest ResponseYou've already chosen the best response.2
Observe that a perfect square is in the form \((a + b)^2 = a^2 + 2ab + b^2\). The first term is \(x^2 \) so we get an idea that the perfect square is in the form \((x + b)^2\). Now the middle term is \(2ab\) and here it is \(14x\). We know that \(a = x\) and so \(2x b = 14x \Rightarrow b = 7\). And so we have \((x + 7)^2 = x^2 + 14x + 49\). There's another technique which you can use formally, which is called "Completing the Square". It's just a ripoff of what I did above.
 one year ago

ParthKohli Group TitleBest ResponseYou've already chosen the best response.2
That technique says that you get the half of the coefficient of \(x\), and square it to get the last term. So you get the half of \(14\) which is \(7\). The square of that is \(49\).
 one year ago

Jhannybean Group TitleBest ResponseYou've already chosen the best response.0
dw:1369717242091:dw
 one year ago

Tabbiejack Group TitleBest ResponseYou've already chosen the best response.0
ok it is easier to see it like that
 one year ago

Tabbiejack Group TitleBest ResponseYou've already chosen the best response.0
I have another question if you don't mind
 one year ago

Tabbiejack Group TitleBest ResponseYou've already chosen the best response.0
Graph the set of points. Which model is most appropriate for the set? ( 1, 20), (0, 10), (1, 5), (2, 2.5)
 one year ago
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