How do you solve #p^ { 2} - p - 20= 0#?

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Answer 1 · 2016-11-30T22:39:09

#p = 5# and #p = -4#

First, you need to factor this equation by playing with pairs of numbers which multiply to #20# giving:

#(p - 5)(p + 4) = 0#

Now we can solve:

#p - 5 = 0# and #p + 4 = 0#

#p - 5 = 0#

#p - 5 + 5 = 0 + 5#

#p = 5#

and

#p + 4 = 0#

#p + 4 - 4 = 0 - 4#

#p = -4#