(2a-5)^2-(2a+3)^2=-80
(2a-5)^2 - (2a+3)^2=-80 (2a-5-2a-3)(2a-5+2a+3)=-80 -8(4a-2)=-80 4a-2= 10 4a=10+2 4a=12 a=3
(2а - 5)^2-(2а+3)^2=-80; 4а^2-20а+25-4а^2-12а-9=-80: 32а+16=-80; 32а=-96; а=-3;