How do you write #d^2-18d+80# in factored form?

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Answer 1 · 2015-09-16T15:57:01

#color(blue)((d-8)(d-10) # is the factorised form of the expression.

#d^2 -18d +80#

We can Split the Middle Term of this expression to factorise it.

In this technique, if we have to factorise an expression like #ad^2 + bd + c#, we need to think of 2 numbers such that:

#N_1*N_2 = a*c = 1*80 = 80#
and
#N_1 +N_2 = b = -18#

After trying out a few numbers we get #N_1 = -10# and #N_2 =-8#
#-10*-8 = 80#, and #(-10)+(-8)= -18#

#d^2 -18d +80= d^2 -10d-8d +80#

#=d(d-10) -8(d -10)#

#=color(blue)((d-8)(d-10) #