How do you factor #7x^2 -15x+2#?

1 Answer
Don't Memorise
May 22, 2015

#7x^2 -15x+2#

We can Split the Middle Term of this expression to factorise it
In this technique, if we have to factorise an expression like #ax^2 + bx + c#, we need to think of 2 numbers such that:

#N_1*N_2 = a*c = 7*2 = 14#
and,
#N_1 +N_2 = b = -15#

After trying out a few numbers we get #N_1 = -14# and #N_2 =-1#
#(-14)*(-1) = 14#, and #(-14)+(-1)= -15#

#7x^2 -15x+2 = 7x^2 -14x - x +2#
#= 7x(x-2) -1(x-2)#
#=(7x-1)(x-2)# , this is the factorised form

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