How do you solve a^4-1=0?

2 Answers
Jan 6, 2016

a=1,-1

Explanation:

a^4-1=0

a^4=1

The only solutions of a could be 1 and -1 because,

1*1*1*1=1

-1*-1*-1*-1=1

Jan 6, 2016

a=+-1

Explanation:

alternatively

(a^4-1)=(a^2+1)times(a^2-1)=(a^2+1)times(a+1)times(a-1)=0
Now a moltiplation is zero when the factors are zero
(a^2+1)=0 cancel(EE) x in RR (no Real solutions)
(a+1)=0; a=-1
(a-1)=0; a=+1