PLEASE SOMEONE HELP! HOW DO I AWNSER THIS QUESTION:

  • 0 votes

Solve x (squared) +5x+4=0

Posted Sun 29th May, 2011 @ 18:30 by summer2011

5 Answers

  • 1 vote

This is how I do it, very clear steps so it should be easy to understand, (x^2 is x squared):

x^2+5x+4 = 0

x^2+x+4x+4 = 0

x(x+1)+4(x+1) = 0 

(x+4) (x+1) = 0 

x=-4 or x=-1

Answered Sun 29th May, 2011 @ 22:12 by N. M
  • 0 votes

@Falak Hussain

"   So the first thing you have to do is factor

x (square) + 5x + 6 = (x + 4)(x + 1)

Set this equal to zero

(x + 4)(x + 1) = 0

Solve each factor

x + 4 = 0             x + 1 = 0
x = 4                  x = 1   "

WRONG

x+4=0     and   x+1=0

Therefore x=-4   and   x=-1


Answered Sun 29th May, 2011 @ 20:44 by Chris
Edited by Chris on Sun 29th May, 2011 @ 20:50
  • -1 votes

Okay so you have to do factor and sum, which two numbers multiply to get 4 , and add to get 5?

The answer is 4 and 1 , so its (x+4)(x+1) ;)

Answered Sun 29th May, 2011 @ 18:35 by Lamise Hassan
  • -1 votes

This is a classic example of a Quadratic Equation

x² + 5x + 4 = 0

1. Look at the constant (+4 in this case). Find its factors:

1x4=4

2x2=4

therefore we might say   (x+2)(x+2)=0

This is incorrect since when expanded:

*** + Xx2 + Xx2 + 4 = X² + 4x + 4

Therefore the quadratic must include the OTHER paired factors (1 and 4)  

(x+1)(x+4)=0

To solve,

(x+1) = 0   or   (x+4)=0

x=-1   or   x=-4

Answered Sun 29th May, 2011 @ 20:49 by Chris
Edited by Chris on Sun 29th May, 2011 @ 20:51
  • -1 votes

factorise it. then make each bracket =0 

Answered Mon 30th May, 2011 @ 11:03 by Georgina