Question

x la a doua minus 2.8(6) plus 0.91(6) egal 0​

Answer 1

Răspuns:

$x_{1} = \frac{\sqrt{195} }{10}$

$x_{2} = -\frac{\sqrt{195} }{10}$

Explicație pas cu pas:

$x^{2} - 2,8(6) + 0,91(6) = 0$

$x^{2} - \frac{286-28}{90} + \frac{916-91}{900} = 0$

$x^{2} - \frac{258}{90} + \frac{825}{900} = 0$

$x^{2} - \frac{2580}{900} + \frac{825}{900} = 0$

$x^{2} - \frac{1755}{900} = 0$

$x^{2} = \frac{1755}{900}$

$x_{1} = \sqrt{\frac{1755}{900} } = \frac{3\sqrt{195} }{30} = \frac{\sqrt{195} }{10}$

$x_{2} = -\frac{\sqrt{195} }{10}$

Answer 2

Răspuns:

x=+-rad(1.95)=aprox +-1.4

Explicație pas cu pas:

x²-2.8(6)+0.91(6)=0

Putem transforma 2.8(6) si 0.91(6) in fractii, dar ar fi pierdere de vreme. Trebuie sa gindim un pic:

2.8(6)=2.86+0.00(6)

0.91(6)=0.91+0.00(6)

Cind le scadem pe astea obtinem:

2.8(6)-0.91(6)=2.86-0.91=1.95

Revenim la exercitiul nostru:

x²-2.8(6)+0.91(6)=x²-[2.8(6)-0.91(6)]=x²-1.95=0

Deci x²=1.95. Sau x=+-rad(1.95)

Daca era 1.96, atunci rad(1.96)=1.4

Deci x=+-rad(1.95)=aprox +-1.4