How do you solve #49a^2-1=80#?

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Answer 1 · 2018-05-02T00:41:11

#a=+-9/7#

#49a^2-1=80#

#49a^2-81=0 rarr# This is an example of difference of squares

Difference of squares: #a^2-b^2=(a+b)(a-b)#

#(7a+9)(7a-9)=0#

#7a+9=0#

#7a=-9#

#a=-9/7#

#7a-9=0#

#7a=9#

#a=9/7#