How do you solve 2x^2+x-1=9?

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Answer 1 · 2018-05-08T14:08:31

#x=-5/2 or x=2#

#2x^2+x-1=9 => 2x^2+x-10=0#

#(2x+5)(x-2)=0#

#2x+5=0 or x-2=0#

#2x=-5 or x=2#

#x=-5/2 or x=2#

Answer 2 · 2018-05-08T14:13:16

#x=-5/2 , 2#

let,
#2x^2+x-1-9=0#
#2x^2-4x+5x-10#=0 (we get this by factorizing)
#2x(x-2)+5(x-2)#=0
#(2x+5)(x-2)=0#
#therefore##x= -5/2,2#

Answer 3 · 2018-05-08T15:39:17

#x=-5/2# and #x=2#

Set equal to 0:

#2x^2+x-1=9#

#rArr 2x^2+x-10=0#

Factorise:

#2x^2-4x+5x-10#

#rArr 2x(x-2)+5(x-2)#

#rArr (2x+5)(x-2)#

Set equal to 0:

#2x+5=0#

#rArr 2x=-5#

#rArr x=-5/2#

#x-2=0#

#rArrx=2#