Question

calcule 2x² - X + 3 para os seguintes valores de x;
2
-1
1/3
-1/2​

Answer 1

Explicação passo-a-passo:

$2x {}^{2} - x + 3$

$para \: \: x = 2$

$2 \times (2) {}^{2} - 2 + 3 = 2 \times 4 - 2 + 3 = 8 - 2 + 3 = 9$

$para \: \: x = - 1$

$2 \times ( - 1) {}^{2} - ( - 1) + 3 = 2 \times 1 + 1 + 3 = 2 + 1 + 3 = 6$

$para \: \: x = \frac{1}{3}$

$2.( \frac{1}{3} ) {}^{2} - \frac{1}{3} + 3 = 2. \frac{1}{9} - \frac{1}{3} + 3 = \frac{2}{9} - \frac{1}{3} + 3$

$mmc = 9$

$\frac{2 - 3 + 27}{9} = \frac{26}{9}$

$para \: \: \: x = - \frac{1}{2}$

$2.( - \frac{1}{2} ) {}^{2} = ( - \frac{1}{2} ) + 3 = 2. \frac{1}{4} + \frac{1}{2} + 3 = \frac{1}{2} + \frac{1}{2} + 3 = \frac{2}{2} + 3 = 1 + 3 = 4$