При каких значениях а и b парабола у=аx^2+bx-4 проходит через точки С(-3;8)и D(1;4)?​

1) 39;

2) -1,44;

3) 187/324;

4) -11/20;

5) 0;

6) -27 3/36;

7) 800

Пошаговое объяснение:

1) 20² - 19² = (20 - 19)(20 + 19) = 1 * 39 = 39;

2) 3,5² - 3,7² = (3,5 - 3,7)(3,5 + 3,7) = (-0,2) * 7,2 = -1,44;

3) (7/9)² - (1/6)² = (7/9 - 1/6)(7/9 + 1/6) = 11/18 * 17/18 = 187/324;

4) (3/10)² - (4/5)² = (3/10 - 4/5)(3/10 + 4/5) = -1/2 * 11/10 = -11/20;

5) (2 1/7)² - (2 1/7)² = (2 1/7 - 2 1/7)(2 1/7 + 2 1/7) = 0 * 4 2/7 = 0;

6) (5 1/6)² - (7 1/3)² = (5 1/6 - 7 1/3)(5 1/6 + 7 1/3) = -13/6 * 75/6 = -27 3/36;

7) 54² - 46² = (54 - 46)(54 + 46) = 8 * 100 = 800

B^2 - 9y^2 : 4b^2 +12by+9y^21) 5(x+4y)/ 15(x+4y) = 1/3
2) 8a^2+40ab : ab+5b^2 = 8a (a + 5b) / b(a+5b) = 8a/b
3) 8ab : 4a^2 b^2+8ab^3 = 8ab / 4ab^2 (a +2b) = 2/b (a+2b)
4) x^2 -9 : 4x-12 = (x-3)(x+3) / 4(x-3) = x+3/4
5) 3a+15b : a^2 - 25b^2 = 3(a+5b) / (a-5b)(a+5b) = 3/a+5b
6)  y^2+4y+4 : y^2 +2y = (y+2)^2 / y(y+2) = y+2/y
7) b^2 +10b+25 : b^2 -25 = (b+5)^2 / (b-5)(b+5) = b+5/b-5

4b^2 - 9y^2 : 4b^2 +12by+9y^2 = (2b-3y)(2b+3y)/ (2b+3y)^2 = 2b-3y/2b+3y = 2*(-1/4) - 3* (5/6) / 2*(-1/4) - 3*(-5/6) = -0.5 + 2.5 / -0.5 +2.5 = 2/2 = 1