Question

Упростите выражение
(a-c)(a+c)-(a-2c)^2

Answer 1

$(a-c)(a+c)-(a-2c)^2 = 4 a c - 5 c^2 = c(4 a - 5 c)$

Answer 2

а^2 - с^2 - а ^2 +4с^2=с^2-4с^2=-3с^2