а) (у – 6)^2 – 9у^2 = у^2 - 12у + 36 - 9у^2 = -8у^2 - 12у + 36.
б) с^2 – d^2 – с + d = (c - d)(c + d) - (c - d) = (c - d)(c + d - 1).
а) (у – 6)^2 – 9у^2 = у^2 - 12у + 36 - 9у^2 = -8у^2 - 12у + 36.
б) с^2 – d^2 – с + d = (c - d)(c + d) - (c - d) = (c - d)(c + d - 1).