Solve (x – 7)(x + 4) = 0. find x?

2 answers of x

1 Answer
Timber Lin
Dec 18, 2017

#x=-4,7#

Explanation:

the only way the product of #x-7# and #x+4# can be #0# is if #x-7# is #0#, #x+4# is #0#, or both #x-7# and #x+4# are #0#. otherwise, the product would be some nonzero number. this rule is the zero product property.

since #x-7# and #x+4# will always be different, they can't both be #0#.
therefore, #x-7=0# or #x+4=0#, so #x=7# or #x=-4#.

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