Question

5) 2x(x + 2) = 8x+3;
Срочнооо ​

Answer 1

$2x(x + 2) = 8x+3\\2x^{2} +4x=8x+3\\2x^{2}+4x-8x-3=0\\2x^{2}-4x-3=0\\D=(-4)^{2}-4*2*(-3)=16+24=40\\x_{1} =\frac{4-\sqrt{40} }{2*2} =\frac{4-2\sqrt{10} }{4} = \frac{2(2-\sqrt{10}) }{4} = \frac{2-\sqrt{10} }{2} = \frac{1}{2}(2-\sqrt{10}) \\x_{2} =\frac{4+\sqrt{40} }{2*2} =\frac{4+2\sqrt{10} }{4} = \frac{2(2+\sqrt{10}) }{4} = \frac{2+\sqrt{10} }{2} = \frac{1}{2}(2+\sqrt{10})$

Answer 2

Решение:

2x(x + 2) = 8x + 3

2x² + 4x = 8x + 3

2x² - 4x - 3 = 0

D = 4² + 4· 2 · 3= 40

$x_1 = \dfrac{4 - \sqrt{40} }{4} = 1 -\dfrac{\sqrt{10} }{2}\approx -0.581$

$x_1 = \dfrac{4 + \sqrt{40} }{4} = 1 +\dfrac{\sqrt{10} }{2}\approx 2.581$