Question

what value of c makes this a perfect square?
4x^2+20x+c

Answer 1

someone?

Answer 2

@amistre64

Answer 3

@Luigi0210

Answer 4

@jdoe0001

Answer 5

@ashleyvee

Answer 6

nevermind...its 25:)
figured it out

Answer 7

$$\bf
4x^2+20x+c\\
\text{grouping the "x"s and common factoring it}\\
(4x^2+20x) +c\\
\text{keep in mind a perfect square trinomial is}\\
(a\pm b)^2 = a^2\pm 2ab + b^2\\
(4x^2+20x+\square ?) +c\\
\color{blue}{\text{or as in }}\\
((2x)^2+2(x)(\square ?)+\square?^2)+c
$$
so what number there do we need to get the perfect square triinomial?

Answer 8

thanks...

Answer 9

hmm, I may have overdone but anyhow

Answer 10

should be just => \(\bf ((2x)^2+2(x)(\square ?)+\square?^2)\)
and THAT VALUE will be "c"

Answer 11

its ok..

Answer 12

you have a medal!
lol

Answer 13

hheehe, so, did you get the number?

Answer 14

yeah 25...right?

Answer 15

25, root of 25 is 5

2(x)(5) = 10x
but you'd need 20x

Answer 16

ok thanks...got it...next question:)
im in the middle of a really long math assignment:P