Question

Dau corona si prieteni mei dau laik si stele va rog ​

Answer 1

Răspuns:

3.

a) -x²+2x=0

a=-1 ; b=2;c=0

∆=b²-4ac

∆=2²-4×(-1)×0

∆=4

$x1= \frac{ - b + \sqrt{delta} }{2a } \\ x1 = \frac{ - 2 + \sqrt{4} }{2 \times ( - 1) } \\ x1 = \frac{ - 2 + 2}{ - 2 } \\ x1 = \frac{0}{ - 2} \\ x2 = \frac{ - 2 - 2}{ - 2} \\ x2 = \frac{ - 4}{ - 2} \\ x2 = 2$

b)

x²-4x-21=0

a=1;b=-4;c=-21

∆=16+84

∆=100

$x1 = \frac{ 4 + \sqrt{100} }{2} \\ x1 = \frac{4 + 10}{2} \\ x1 = \frac{14}{2} \\ x1 = 7$

$x2 = \frac{4 - \sqrt{100} }{2} \\ x2 = \frac{4 - 10}{2} \\ x2 = \frac{ - 6}{2} \\ x2 = - 3$

4

a)

y=2x+3

y=x²

=>

2x+3=x²

-x²+2x+3=0

a=-1;b=2;c=3

∆=2²+12

∆=4+12

∆=16

$x1 = \frac{ - 2 + \sqrt{16} }{ - 2} \\ x1 = \frac{ - 2 + 4}{ - 2} \\ x1 = \frac{2}{ - 2} \\ x1 = - 1$

$x2 = \frac{ - 2 - 4}{ - 2} \\ x2 = \frac{ - 6}{ - 2} \\ x2 = 3$

b este in poza

sper ca te-am ajutat! ʕ •ᴥ•ʔ