Question

@ganeshie8

Answer 1

Which questions?

Answer 2

3 a)

Answer 3

Volume of cuboid = length * width * height

Answer 4

3.
a. V = 1/3bh
V = length*width*height
V= b-5*3b*b+1
V = 15b²-b-1

Answer 5

correct?

Answer 6

Nope

Answer 7

Don't forget the parentheses

Answer 8

V=(b-5)(3b)(b+1)

Answer 9

V = 15b²-b-1

Answer 10

the answer?

Answer 11

No that's not correct

Answer 12

how?

Answer 13

How did you get 15b^2-b-1?

Answer 14

For 3 a) you wrote:

V = length*width*height - this is correct

V= b-5*3b*b+1 - this is not correct because you forgot the parentheses. It should be

V=(b-5)*(3*b)*(b+1)

And the answer to that is going to be

V=(b-5)*(3*b)*(b+1)=(3*b^2-15*b)*(b+1)=3*b^3-15*b^2+3*b^2-15*b=3*b^3-12*b^2-15*b or b*(3*b^2-12*b-15) or 3*b*(b^2-4*b-5).

Solving the quadratic form inside the parentheses you have the two roots equal to 5 and -1. So the expression now becomes:

V=3*b*(b^2-4*b-5=3*b*(b-5)*(b+1).

Side note: A quick way to tell whether or not you're right with the answer is to check the polynomial form of your answer. If it's something^2 it's an area (hence why we call it the "square" of a number). If it's something^3 it's a volume (hence why we call it the "cube" of a number).

Answer 15

@kc_kennylau

Answer 16

Is that correct for 3/c :

C) V = 1/3bh
V = 1/3(L*W) h
V = 1/3( (2k+3)*(k-2) ) 3k
V = k(2k²+3k - 4k - 6)
V = k(2k² - k - 6)
V = 2k^3 - k^2 - 6k

Answer 17

@kc_kennylau

Answer 18

Perfect

Answer 19

My friend said that the formula is 1/2bhl

Answer 20

Not 1/3bhl

Answer 21

@kc_kennylau

Answer 22

Then tell your friend that he's wrong.

Answer 23

P.S. 1/2*b*h is for triangle

Answer 24

Ok thanks that's hat I told her ..

Answer 25

Thanks

Answer 26

No problem