Question

z2 – z – 56 how to factor completely this problem?

Answer 1

(z - 8)(z + 7)

Answer 2

Which gives you z = 8 and z = -7 as your roots.

Answer 3

I get the opposite (z-7)(z+8) are they the same?

Answer 4

no they are not the same.
FOIL your answer you would get z^2 + z - 56

Answer 5

you want two numbers that multiply to -56 and add up to -1
-8 and 7 will do that
8 and -7 will get you a sum of +1

HOWEVER, the ROOTS of the equation, as BubbaMurphy says are 8 and -7
because you have
(z - 8)(z + 7) = 0
so you get
z - 8 = 0
z + 7 = 0
giving you z = 8 and -7

Answer 6

oh okey thanks guys u save me

Answer 7

No problem