a)-(a-5)(a+3)-(1-a)²=
c)(2a+0,5)²-(0,5-2a)²=
e)25x²+(7+5x)(7-5x)=

A)  - (a-5)(a+3)-(1-a)^2= - (a^2+3a-5a-15)- (1-2a+a^2) = 
       - (a^2 -2a+15 )-(1-2a+a^2)=  - a^2 +2 a - 15 -1+2a -a^2 =
       -2a^2 + 4a -16= -2 ( a^2 -2 a +8 )
 C ) ( 2 a+ 0.5)^2 - ( 0.5 - 2 a )^2 = ( 0.5 + 2 a )^2 - ( 0 . 5 - 2 a )^2=
       
       0.25 +2 a + 4 a ^2 - 0.25+ 2 a - 4 a^2= 4 a .

e )  25 x ^2 +( 7+5 x) (7-5x )=  25x^2 + 49-25x^2=49