Question

Rezolvați ecuatiile 1:2(x-3)-13=x-21 ​

Answer 1

Explicație pas cu pas:

1:(2x-6) - 13 =x-21

1:(2x-6)= x- 21+13

1: (2x-6)= x-8 |*(2x-6)

1=(x-8)(2x-6)

${2x}^{2} - 6x - 16x + 48 = 1$

${2x }^{2} - 22x + 47 = 0$

$delta = {b}^{2} - 4ac$

$delta = { - 22}^{2} - 4 \times 2 \times 47$

$delta = 108$

$x1.x2 = ( -b \frac{ + }{ - } \sqrt{delta} ) \div \: 2a$

$x1.x2 = (- ( - 22) \frac{ + }{ - } \sqrt{108}) \div (2 \times 2)$

$x1.x2 = (22 \frac{ + }{ - } 6 \sqrt{3} ) \div 4$

$x1 = 2(11 + 3 \sqrt{3} ) \div 4 =( 11 + 3 \sqrt{3} ) \div 2$

$x2 = 2(11 - 3 \sqrt{3} ) \div 4 = (11 - 3 \sqrt{3} ) \div 2$