Answer:
[tex]a=[/tex] ±[tex]5[/tex]
Step-by-step explanation:
[tex]a^{2} =25[/tex]
equal to zero
[tex]a^{2} -25=0[/tex]
factor: difference of squares
[tex](a+5)(a-5)=0[/tex]
first factor:
[tex]a+5=0\\a_{1} =-5[/tex]
second factor:
[tex]a-5=0\\a_{2} =5[/tex]
Hope this helps