How do you factor #y=z^2 + 3z - 4 #?

1 Answer
Feb 22, 2016

Answer:

Factors of #z^2+3z−4# are #(z-1)(z+4)#

Explanation:

To find the factors of #az^2+bz+c#, one should find factors of #a*c# whose sum is #b#.

As the function is #z^2+3z−4#, one should find factors of #1*(-4)# or #-4# whose sum is #3#.

These are #-1# and #4#. Hence splitting middle term this way.

#z^2+3z−4# = #z^2-1z+4z−4# or

#z(z-1)+4(z-1)# or #(z-1)(z+4)#