Question

якласс 8 класс срочно математика!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 1

Ответ: х1 = 6,8

x2 = 23

$5.7(x - 6.8)(x - 23) = 0 \\ (x - 6.8)(x - 23) = 0 \\ {x}^{2} - 23x - 6.8x + 156.4 = 0 \\ {x}^{2} - 29.8 + 156.4 = 0 \\ \\ d = {29.8}^{2} - 4 \times 1 \times 156.4 = 262.44 \\ d > 0 \\ x1 = \frac{29.8 + \sqrt{262.44} }{2 \times 1} = \frac{46}{2} = 23 \\ x2 = \frac{29.8 - \sqrt{262.44} }{2 \times 1} = \frac{13.6}{2} = 6.8$

Answer 2

Ответ:   6.8.  23.

Объяснение:

5,7(x²-23x-6.8x+‬156.4)=0;

5.7(x²-29,8x+156,4)=0;

5.7≠0.      Следовательно  

x²-29,8x+156,4=0;

a=1;  b=-29.8;  c= 156.4;

D = b²-4ac = (-29,8)²-4*1*156.4 = 888.04 - 625.6= 262.44>0 - 2 корня

x1,2=(-b±√D)/2a= (-(-29.8)±√262.44)/2*1=(29.8±16.2)/2;

x1 = (29.8+16.2)/2 = 23;

x2 = (29.8-16.2)/2=6.8.