How do you solve #(x-8)(x-1)=0#?

1 Answer
May 24, 2015

One way of seeing this is using some logic and math.

If you have a product that equals zero, as in this case, you must agree that at least one of the factors is zero.

Thus, either #x-8# and/or #x-1# equals zero.

Thus, #x_1=8# and #x_2=1#.

Another way is distributing these factors. To distribute, you need to multiply each term of the first by all the terms in the second, as follows:

#(x-8)(x-1)#

#(x*x)+(x*(-1))+((-8)*x)+((-8)(-1))#
#x^2-x-8x+8#
#x^2-9x+8#

And now let's find its roots. I'll use Bhaskara here.

#(9+-sqrt(81-4(1)(8)))/2#
#(9+-7)/2#
#x_1=(9+7)/2=8#
#x_2=(9-7)/2=1#

:)