8. The area of a rectangular painting is given by the trinomial x2 + 4x – 21. What are the possible dimensions of the painting? Use factoring. (1 point)

Question

8.   The area of a rectangular painting is given by the trinomial x2 + 4x – 21. What are the possible dimensions of the painting? Use factoring.  (1 point)

parthkohli · Answer

Do you know factoring of quadratic expressions?

anonymous · Answer

no. i don't know any of this. honestly. aha.

parthkohli · Answer

Oopsie...

parthkohli · Answer

@Callisto can you continue?

anonymous · Answer

?

lgbasallote · Answer

you quit fast enough @ParthKohli :P

parthkohli · Answer

lgba has a tutorial btw

anonymous · Answer

ok. so i'm assuming you don't know? lololololol.

parthkohli · Answer

I do know.. it's a long explanation. Do you want me to teach it to you?

callisto · Answer

Area = length times width.
Since you're given the area, you need to factorise the expression given for the area. Am I on the right track @ParthKohli ?

parthkohli · Answer

Exactly :D

anonymous · Answer

no. sorry. but when people explain me things over the computer i don't really understand. i'm not smart at all. aha, i'm just trying to pass this final cause i have a 62% and i can't fail the final or i fail the grade.

parthkohli · Answer

lgba....link your tutorial please

callisto · Answer

@ParthKohli I agree :|

lgbasallote · Answer

hmm we can try...

anonymous · Answer

i'm confused?

parthkohli · Answer

http://www.youtube.com/watch?v=nOZTe8jU2g4 Here you go

anonymous · Answer

its not working?

lgbasallote · Answer

lol just teach her parth :p

anonymous · Answer

9.   The area of a rectangular barnyard is given by the trinomial 12x2 + 14x – 40. What are the possible dimensions of the barnyard? Use factoring.  (1 point)

– 4x + 10 and –3x + 4

is that right?

lgbasallote · Answer

close...but no

lgbasallote · Answer

if you multiply that you'll get $$12x^2 - 16x - 30x + 40$$

anonymous · Answer

4x – 10 and 3x + 4

parthkohli · Answer

A very very long explanation....I'll get tired.

lgbasallote · Answer

....is this multiple choice?

anonymous · Answer

yeeah.

lgbasallote · Answer

lol clever ;D

anonymous · Answer

is that the correct answer?

lgbasallote · Answer

i encourage you to solve it though

lgbasallote · Answer

and no it isnt....i shall shush now...

anonymous · Answer

well i don't get it.. so i don't know.

parthkohli · Answer

Let me explain it in a nutshell. 
You must split the middle term so that in the expression $ax^2 + bx + c$, we have the sum of the two split co-effecients as b. Also, the split co-efficients must have a product as the product of a and c.

lgbasallote · Answer

this is a bad technique...but do trial and error on your multiple choice :p

parthkohli · Answer

Lol this is the only way to factor :P

lgbasallote · Answer

<---does trial and error

anonymous · Answer

..do you want to know how to do it? or just know the answer?

parthkohli · Answer

You can multiply in all the choices and see if the product is same as the trinomial.

callisto · Answer

Sorry.. I'm not in the mood of writing today :(

anonymous · Answer

the answer.

parthkohli · Answer

Not allowed to give the answer.

anonymous · Answer

ok.

lgbasallote · Answer

do you know how to multiply binomials?

parthkohli · Answer

$\Large \color{Black}{\Rightarrow x^2 + 4x + 21 = x^2 + 7x - 3x + 21 }$

Enough of hints.

anonymous · Answer

(x+7)*(x-3)

factor the equation and 

solutions are easily visable as 

7 and 3

parthkohli · Answer

*facepalm* @timo86m

anonymous · Answer

I am asking

anonymous · Answer

whats your question @timo86m

anonymous · Answer

would 7 and 3 be the answer it will be actually -7 and 3 but I think they are absolute values.

anonymous · Answer

just message me @timo86m