Question

(х+4)(х-4)+(х-5)(х+4)=0

Answer 1

( x + 4 )( x - 4 ) + ( x - 5 )( x + 4 ) = 0 
( x + 4 )( x - 4 + x - 5 ) = 0 
( x + 4 )( 2x - 9 ) = 0 
x + 4 = 0 
x = - 4 
2x - 9 = 0 
x = 4,5 
Ответ 9,5 ; - 4