Question

What is the value of c so that y = x^2 + 9x + c is a perfect trinomial?
a) 18
b) 9/2
c) 9/4
d) 81/4

I WILL GIVE MEDAL AND BECOME A FAN

Answer 1

@ravikr.iit

Answer 2

Is D the correct answer?

Answer 3

You can test it yourself! I don't believe that it is the correct answer...

Answer 4

Or maybe it is...

Answer 5

It might be...

Answer 6

A perfect trinomial factors into a squared binomial like this: \( (x + h)^2 \)
This expands out to \(x^2 + 2h x + h^2 \)
We can then compare coefficients between the trinomials.
2h = 9
h squared will become the necessary addition to make a perfect square trinomial, c = h^2.

Answer 7

Either way, whoever does know for sure should show justification for learning purposes. Thank you @AccessDenied .

Answer 8

So, I agree with both of you now :)

Answer 9

yeah
\[(x+9/2)^{2}\] is perfect trinomial

Answer 10

Thanks everyone.

Answer 11

I didn't do too much, but you're welcome :)

Answer 12

I have a few more questions, here is one of them:

What are the solutions of the equation?
0=x^2+3x-10

a)x+5,2
b)x=-4,-2
c)x=-5,2
d)x=5,-2

Answer 13

a)x=5,2* sorry

Answer 14

Have you attempted to factor the quadratic? Often this is helpful to split it into single linear equations.
A*B = 0 means A=0 or B=0.

Answer 15

FYI, it's not called a perfect trinomial. It's called a perfect square trinomial.

Answer 16

I have one more question:

A ball is thrown into the air with an upward velocity of 32 feet per second. Its height, h, in feet after t seconds is given the function h(t)=-16t^2+6. How long does it take the ball to reach its maximum height? What is the ball's maximum height? Round to the nearest tenth, if necessary.

a)reaches a maximum height of 22 feet after 1.00 seconds.
b) reaches a maximum height of 22 feet after 2.00 seconds.
c)reaches a maximum height of 44 feet after 2.17 seconds.
d)reaches a maximum height of 11 feet after 2.17 seconds. @AccessDenied @ravikr.iit @theEric @ranga can you help?

Answer 17

at max. hight velocity=o
so differentiate the function h(t) and u'll find velocity put is zero and solve for t
u'll get the time for max hight.
then putt this value in function of hight h(t) u'll get the max hight

Answer 18

that would be the right idea, although i suspect this is algebra 2 and the operation of differentiation may not be known. here.
instead, there is an alternative using the vertex form or x = -b/2a to find vertex of the parabola, the high point.

Answer 19

But we can just look at it more simply... In case we haven't learned differentiation. What \(t\) will make that function largest? Well, the \(t\) multiplies a negative......

Ooo.... @AccessDenied has a MUCH more relevant idea :)

Answer 20

And it gives the same result! :)

Answer 21

Okay thanks again(:

Answer 22

you're welcome! :)

Answer 23

Take care!

Answer 24

Are you sure h(t) = -16t^2 + 6?
Is the "t" term missing?

Answer 25

@ranga it is odd... I just assumed it to be written correctly, although it contradict the wording "thrown into the air." Without that \(t\) term, it is not thrown. Rather, it is dropped from six feet above the ground somewhere very roughly around sea level...

Answer 26

@nichole_rawr_ did you see what ranga posted?