Question

solve 3x^2-36x>0

Answer 1

i can try it to solve

Answer 2

thanks so much

Answer 3

\[3x ^{2}-36x>0\]

Answer 4

or,\[3x ^{2}>36x\]

Answer 5

or,\[x>12\]

Answer 6

take 3x^2-36x
factor out 3x
3x(x-12)>0
x<0 or x>12

Answer 7

what happened t 3x outside the bracket

Answer 8

it was factored out

Answer 9

how???.

Answer 10

um, I don't really know how to explain this
here, i'll explain it graphically instead.

Answer 11

okk

Answer 12

coz if u solve this q' on the casio class pad it gives u a way different answer

Answer 13

graph y=3x^2-36x
look at where y=0
then look at where y<0

Answer 14

what answer does it give?

Answer 15

x-3.5, if rounded off

Answer 16

that's weird.

Answer 17

yeahhh.. so

Answer 18

ah, you forgot the x on the end. y=3x^2-36x

Answer 19

wt grade r u in, not 2 be personal

Answer 20

don't have 2 answer this

Answer 21

uu.. interesting

Answer 22

3x^2-36x>0 You can solve this just like a regular equation. To make it look a bit simpler, we can take the greater than sign and replace it with an equals sign for now. So 3x^2-36x=0. Since there is a x in both terms, we can divide it off and put it outside some parentheses. That gives you x(3x-12)=0. Go ahead and put the greater than back now. x(3x-12)>0. Now, you can look at it like two separate, smaller inequalities. x>0 and 3x-12>0. Now, you can solve both for x. x>0 is done already. To get the other, add 12 to both sides. 3x-12+12>0+12, 3x>12. Now divide both sides by 3. IMPORTANT: remember to always flip the inequality when you divide! So it becomes less than. 3x/3<12/3, x<4. So your answers are x>0, x<4. You can also combine them to get 0<x<4. That combined statement is probably the answer the Class Pad gave.

Answer 23

@singlesixx you got a bit of the math wrong, and we already figured out that the classpad gave the wrong answer because of operator error

Answer 24

What part of the math did I get wrong?

Answer 25

3x^2-36 is not the same as x(3x-12)

Answer 26

you factored the 3 out of the 36 but not out of the 3x

Answer 27

Wow. I am not the smartest person. I had 3x(3x-12), and changed it to what's there now.

Answer 28

it's fine, anyone could have made that mistake

Answer 29

it's just a calculation error, your theory was right.