Question

19. What is the value of c so that x² – 11x + c is a perfect-square trinomial?
121

–

Answer 1

ignore the 121 lol

Answer 2

well, a perfect square is of the form (a+b)^2, which expands out to:

a^2+2ab+b^2 lets compare that to what you are given
x^2 –11x + c

looks like a=x, and 2bx = -11x

id say b = -11/2

so c = b^2

Answer 3

i have worked it out and i cannot find the right answer.. the choices are,
121

121 over 4

-11 over 4

121 over 2

Answer 4

....

id say b = -11/2

so c = b^2

what praytell is (-11/2)^2 ?

Answer 5

is this completing the square?

Answer 6

-11/4?

Answer 7

no, -11/4

you got the /4 part right

now what is (-11)^2 ?

Answer 8

121/4.. im pretty sure that it!

Answer 9

\[\frac{-11}{2}*\frac{-11}{2}=\frac{(-11)^2}{(2)^2}\]

Answer 10

yes, that would be it :)

Answer 11

okay thank you soo much! XD