Some math question, urgent help!
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Simplify the following:
11c/15d^2 x 18cd/44. / is the fraction thing.
Sorry if it is very very confusing, i having math exam tml. Need help, thank you -
11c/15d² * 18cd/44
= c/15d * 18c/4 ==> (11 cancel off, d cancel off)
= c/5d * 6c/4 ==> (3 cancel off)
= 3c²/10
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Okay, thank you eagle after reading your reply i understand. i think u miss out the 5d * 4
Should be = 3c²/10d
Sorry, 2y - 1/3 = 7. I totally forget the formula, i only in sec3 NT math. I skip too much lesson. And what the meaning of mean, median, mode? Mean is average?
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paiseh... most of the times I do mentally and type out
mean is average
mode is most frequent
median is the centre of all the values -
I realise it getting much easier after u explain, i find how stupid i am after i do 2y-1 /3 = 7.
7*3 = 21 + 1 = 22. 2y = 22 y = 11 hahaha. It is okay to ask more question here?
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no problem
go ahead and ask
May I know which level you are at?
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Factorise completely.
2y² - 32. I got answer key, but seem weird. Or i forget the method totally.
Secondary 3, Normal Technical student only. -
Never fear, eagle's sidekick is here!
2y^2 - 32 = (2y-8)(y+4)
Will be posting the method shortly but I have to reserve a spot for my post. =P
This is gonna be a bit hard to explain...
2y^2 - 32 = 2y^2 + 0y -32
First you draw an X. There are four numbers you have to place on each point of the X.
2y -8
X
y 4
The two numbers on the left, when multiplied, must be equal to the the coefficient of y^2 (i.e. The number next to y^2 in your equation). In this case the coefficient is 2, and the only two factors of 2 are 1 and 2. Therefore, we place 2y at the top and 1y below (you can swap them if you want, it doesn't matter.)
On the right side of the X, you again have two numbers. These two numbers, when multiplied, must be equal to the constant, which is in this case -32. There are multiple possible combinations: you could have 1 and -32, 2 and -16, 4 and -8 etc. (Note that you can swap the negative symbols around between the two numbers). The constant is the number in the equation without a y next to it.
However, this is where it gets tricky. Multiply the numbers diagonally across the two lines of the X. In the example of the cross I gave above, I multiply 2y with 4 and y with -8. This results in the numbers 8y and -8y. The two results you get (in this case 8y and -8y) must be equal to the middle term. (In this case, notice the middle term is actually 0y.) Therefore, because 8y and -8y, when added together, = 0y, this is the correct combination.
After that, simply take the top two numbers of the cross and place them together in brackets (2y-8) next to the bottom two numbers, also in brackets (y+4). Your factorisation is complete. The result is (2y-8)(y+4) = 0.
Since (2y-8)(y+4) = 0, Either (2y-8) will be equal to 0 OR (y+4) is equal to 0. This is because for two numbers that are multiplied to be equal to 0, at least one of them will be 0, because anything multipled by 0 IS 0. For example, 1x0 = 0, 2x0 = 0 and so on.
So, we say that:
2y-8 = 0 OR y+4=0
2y = 8 OR y = -4
y = 4
Therefore, y has two possible values: 4 or -4.
Boss eagle, did I do I good job?
Read his answer. I made a stupid mistake. =(
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Originally posted by SGFORUMS PETER:
Factorise completely.
2y² - 32. I got answer key, but seem weird. Or i forget the method totally.
Secondary 3, Normal Technical student only.Hi Peter,
Mr Sean's answer is incorrect. The correct answer should be
Question
Factorise completely.
2y² - 32
Answer
2y^2 - 32
= 2(y^2 - 16)
= 2(y^2 - 4^2)
= 2(y - 4)(y + 4) using the rule a^2 - b^2 = (a-b)(a+b)
Thank you for your kind attention.
Regards,
ahm97sic
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Crap I'm sleepy. =(
Forgot to take out the two.
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Well, skipping lessons is definitely not a good thing...