How to factorise
 
x^3 +3x^2 +28

Asked by tejvarun | 14th Mar, 2017, 01:05: PM

Expert Answer:

begin mathsize 16px style Your space question space is space straight x cubed plus 3 straight x squared plus 28. space This space cannot space be space factorised.
The space correct space question space should space be
straight x cubed plus 3 straight x squared minus 28 straight x equals 0
rightwards double arrow straight x cubed plus 7 straight x squared minus 4 straight x squared minus 28 straight x equals 0
rightwards double arrow straight x squared left parenthesis straight x plus 7 right parenthesis minus 4 straight x left parenthesis straight x plus 7 right parenthesis equals 0
rightwards double arrow left parenthesis straight x plus 7 right parenthesis left parenthesis straight x squared minus 4 straight x right parenthesis equals 0
rightwards double arrow left parenthesis straight x plus 7 right parenthesis straight x left parenthesis straight x minus 4 right parenthesis equals 0
rightwards double arrow straight x left parenthesis straight x plus 7 right parenthesis straight x minus 4 right parenthesis equals 0
rightwards double arrow straight x equals 0 space or space straight x plus 7 equals 0 space or space straight x minus 4 equals 0
rightwards double arrow straight x equals 0 space or space straight x equals negative 7 space or space straight x equals 4 end style

Answered by Rashmi Khot | 14th Mar, 2017, 02:52: PM