Question #507e9

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Answer 1 · 2017-09-27T04:09:48

#(3x+8)(x-1) =0#

i.e. #x= -2 2/3# or # x=1#

#-3x^2-5x+8=0#

#3x^2+5x-8=0#

The product of coefficient of first and last term is # 3\times-8 = -24#

So we need to find two such numbers whose sum is equal to the middle term #5#and product is #-24#.

#8 # and # -3# are two numbers which sum up to #5#and their product is #-24#. Therefore we write the equation as:

#3x^2 -3x +8x-8=0#

#3x(x -1) +8(x-1)=0#

#(3x+8)(x-1) =0#

Therefore:
#(3x+8) =0 # i.e. #x= -8/3# = #2 2/3#
or
#(x-1) =0# i.e. # x=1#

Answer : #x= -2 2/3# or # x=1#