Question

Given the following perfect square trinomial, fill in the missing term.

4x2 + ___x + 49

Answer 1

for this, i have to put the exact answer in the answer box or i get it marked as wrong. can anyone give me the explaination for this along with the answer clearly marked as the answer ?

Answer 2

well for a perfect square, the bx(what you are trying to find) multipies together the get c)in this case 49),

Answer 3

uhm okk

Answer 4

this is the form of ax^2+bx+c, correct?

Answer 5

i think so

Answer 6

okay, so with knowing that we know that a=4, c=49, yes?

Answer 7

yes

Answer 8

okay, so b is going to be the square root of C.

Answer 9

ok

Answer 10

so what would your answer be?

Answer 11

idk.i have to put the exact answer in or its marked wrong so i dont trust my own judgement.

Answer 12

well what do you think it is and ill tell you.

Answer 13

what is the square root of 49?

Answer 14

7

Answer 15

okay, now since there is a leading coefficient in frontof the x^2 what does that tell you?

Answer 16

i dont have a clue. this is my weakest subject

Answer 17

okay, well with that 4 there, it makes it a little more complicated. @hartnn can probably explain it better.

Answer 18

ok thanks

Answer 19

ok, if the leading co-efficient is not =1, you make it equal to 1
by dividing by 4,
say you missing term is 'm'
so, x^2 + (m/4)x +49/4
got this ?

Answer 20

kinda

Answer 21

so now (last term)^2 = 49/4
then last term =... ?

Answer 22

ok u lost me

Answer 23

if thats a perfect square, then its in the form,
\((a+b)^2 =(a^2+2ab+b^2)\)
right ?
see the last term is b^2, to get 'b' you take square root of last term.
here last term = 49/4
so what is square root of 49/4 ??

Answer 24

7

Answer 25

7 is the square root of 49
i asked square root of 49/4

Answer 26

oh 3.5

Answer 27

yeah.. keep it as 7/2 only.
thats your 'b'
to get the middle term m/4 , just multiply this by 2 ,
7/2 *2 = ... ?