1.
а) (с+7)^2 = с^2 + 14c + 49
б) (5с-2)^2 = 25c^2 - 20c + 4
в) (3х- 4)(3х+4) = 9x^2 - 16
г) (а^2+2)(а^2-2) = a^4 - 4
2.
а)1/16 - б^2 = (1/4 - b)(1/4+b)
б) у^2 + 12у + 36 = (y + 6)^2
3. (3х-у)^2 - 3х(3х+2у) = 9x^2 - 6xy + y^2 - 9x^2 - 6xy = y^2 - 12xy
При у= -3/5 — (-3,5)^2 - 12x * (-3,5) = 12,25 + 42x
4.
а) 5(3mn+1)(3mn-1) = 5 * (9m^2n^2 - 1) = 45m^2n^2 - 5
б) (a^3-b^4)^2 = a^6 - 2a^3b^4 + b^8
в) (c-d)^2-(c+d)^2 = c^2 - 2cd + d^2 - c^2 - 2cd - d^2 = -4cd
5.
а) (5х-1)(5x+1) - (5x+2)^2 = 0
25x^2 - 1 - 25x^2 - 10x - 4 = 0
-10x - 5 = 0
-10x = 5
x = - 0.5
б) 36b^2 - 121 = 0
(6b - 11) * (6b + 11) = 0
6b - 11 = 0 или 6b + 11 = 0
6b = 11 6b = -11
b = 11/6 b = -11/6