3a + 5b - 4a - 2b если a=5, 3, b=1/3

3*5,3+5*1/3-4*5,3-2*1/3=15,9+5/3-21,2-2/3=-5,3+1=-4,3

36a^4 - 25 = (6a^2)^2 - 5^2 = (6a^2 - 5)(6a^2 + 5) 216x^3 - 1 = (6x)^3 - 1^3 = (6x-1)(36x^2+6x+1) 100b^2 - 140bx^2 + 49x^4 = (10b - 7x^2)^2=(10b-7x^2)(10b-7x^2) 125b^3 + 27 = (5b + 3)(25b^2 - 15b + 9) (5a - 1/5)^2 = 25a^2 - 2a + 1/25) (3a - 5b^2)(9a^2 + 15ab^2 + 25b^4) = (3a)^3 - (5b^2)^3 = 27a^3 - 125b^6 (0,8x+ 5)(5 - 0,8x) = (5 + 0,8x)(5 - 0,8x) = 5^2 - (0,8x)^2  = 25 - 0,64x^2 (7x+ 0,4)^2 = 49x^2 + 5,6x + 0,16 (6y + 1)(36y^2 - 6y + 1) = (6y)^3 + 1^3 = 216y^3 + 1 25x^2 + 60xy + 36y^2 = (5x + 6y)^2 = (5x + 6y)(5x + 6y).

(x^2 + x + 4)^2 + 8x(x^2 + x + 4) = - 15x^2 (x^2 + x + 4)(x^2 + x + 4 + 8x) = - 15x^2 (x^2 + x +4)(x^2 +9x + 4) = - 15x^2 x^4 + 9x^3 + 4x^2 + x^3 + 9x^2 + 4x + 4x^2 + 36x + 16 + 15x^2 = 0 x^4 + 10x^3 + 32x^2 + 40x + 16 =0 ( x+ 2)^2(x^2 + 6x + 4) = 0 (x + 2)(x + 2)(x^2 + 6x + 4) = 0 x + 2 = 0 x = - 2 x  + 2 = 0 x = - 2 x^2 + 6x + 4 = 0 d = b^2 - 4ac =36 - 16 = 20 x1 = ( - 6 + 2√5) / 2 = - 2(3 - √5) / 2 = - (3 - √5) = √5 - 3 x2 = ( - 6 - 2√5) / = - 2(3 + √5)/ 2 = - (3 + √5) = - 3 - √5 ответ: x1 = √5 - 3,x2 = -√5 - 3, x3 = - 2,x4 = - 2