Question

2) Calcule usando a fórmula de BASKARA :
a) 4x² - 6x=0
b) 2x²=0
c) x²=0

3) calcule:
a) 5/4 + 1/5
b) 3/5 - 7/3

Answer 1

Explicação passo-a-passo:

2) a) 4x² - 6x = 0

$x = \frac{ - ( - 6) + - \sqrt{ {( - 6)}^{2} - 4 \times 4 \times 0 } }{2 \times 4} \\ \\ x = \frac{6 + - \sqrt{36} }{8} \\ \\ x1 = \frac{6 + 6}{8} = \frac{12}{8} = \frac{3}{2} \\ \\ x2 = \frac{6 - 6}{8} = 0$

b) 2x² = 0

$x = \frac{ - 0 + - \sqrt{ {0}^{2} - 4 \times 2 \times 0} }{2 \times 2} \\ \\ x = \frac{ + - \sqrt{0} }{4} = 0$

c) x² = 0

$x = \frac{ - 0 + - \sqrt{ {0}^{2} - 4 \times 1 \times 0 } }{2 \times 1} \\ \\ x = \frac{ + - \sqrt{0} }{2} = 0$

3) a)

$\frac{5}{4} + \frac{1}{5} = \frac{(5 \times 5) + (4 \times 1)}{4 \times 5} = \frac{25 + 4}{20} = \frac{29}{20}$

b)

$\frac{3}{5} - \frac{7}{3} = \frac{(3 \times 3) - (5 \times 7)}{5 \times 3} = \frac{9 - 35}{15} = - \frac{26}{15}$