Question #0415a

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Answer 1 · 2017-11-03T04:36:25

#x=-4 and -2#

#x^2+6x+8=0#

#=>x^2+2x+4x+8=0#

#=>x(x+2)+4(x+2)=0#

#=>(x+4)(x+2)=0#

Using the zero product property (if #a*b=0#, then #a=0 and b=0#)

#:.x+4=0 and x+2 = 0#

#:.x=-4and-2#

Answer 2 · 2017-11-03T04:37:08

#x=-4 or x= -2#

#x ^2 + 6x + 8 = 0#

Find two such numbers whose sum is coefficient of middle term, i.e. #6#, and product is product of coefficient of first term and last term, i.e. #8#:

Two such numbers are 4 and 2. So rewrite and solve the above equation as:

#x ^2 +2x + 4x + 8 = 0#

# x(x+2) + 4(x+2) = 0 #

#=> (x+4)(x+2)= 0#--------- factorised form.

#therefore (x+4)= 0 => x= -4#
0r
#(x+2) = 0 => x= -2#

Answer : #x=-4 or x= -2#