Question

(7,2-x)(2x+4)=0 ришите быстрей

Answer 1

(7,2-x)(2x-4)=0
7,2-x=0 2x+4=0
x=7,2 x=-2

Answer 2

(7,2-x)(2x+4)=0
$14,4x + 28,8 - 2 x^{2} - 4x = 0$
$10,4x + 28,8 - 2 x^{2} = 0$
Поделим всё на (-2):
$x^{2} - 5,2x - 14,4 = 0$
D = $5,2^2 - 4*(-14,4) = 84,64 = 9,2^2$
$x_{1} = \frac{5,2+9,2}{2} =7,2$
$x_{2} = -2$