Question

can anyone factorise cubics?

2z³+9z²-6z-40

Determine which of (z-2), (z+3) and (z+4) is a factor

Hence write the above equation as a product of linear factors

Answer 1

(z-2)(z+4)(2z+5)

Answer 2

can you please explainthat

Answer 3

we have to find an x value that makes the expression zero, we can do this by evaluating the function at points that could makes this function zero. In this case we notice that 2 makes this function zero.

Answer 4

what we will do is divide this cubic polynomial by z-2. This will help us to get the cubi function into a qudratic function

Answer 5

hm ok

Answer 6

So, after dividion, we : 2x^2+13z+20

Answer 7

so now we have (z-2)(2z^2+13z+20)

Answer 8

now gues what we do???

Answer 9

thats right we factor the quadratic

Answer 10

haha

Answer 11

The quadratic factors to: (2z+5)(z+4).

Answer 12

Now we have the factored form of the cubic polynomial as: (z-2)(z+4)(2z+5)

Answer 13

Does that answer that question??:)

Answer 14

yes thanks... pity the best i can give you is a medal...