Question

formula method 2x^-9x+7=0​

Answer 1

Answer:

$2 {x}^{2} - 9x + 7 = 0 \\ 2 {x}^{2} - 2x - 7x + 7 = 0 \\ 2x(x - 1) - 7(x - 1) = 0 \\ (2x - 7)(x - 1) = 0$

Now,

$2x - 7 = 0 \\ 2x = 7 \\ x = \frac{7}{2}$

or

$x - 1 = 0 \\ x = 1$

Hence,

$x = 1$

or

$x = \frac{7}{2}$

Answer 2

Answer:

Correct question

${2x}^{2} - 9x + 7 = 0.$

Step-by-step explanation:

$Here, a = 2, b = - 9, C = 7$

$∴ \: \: \: \: \: \: \: From \: x = \frac{ - b± \sqrt{ {b}^{2} - 4ac} }{2a}$

$\: \: \: \: \: \: \: \: \: \: \: \: \: x = \frac{ - ( - 9)± \sqrt{ {( - 9)}^{2} - 4.2.7 } }{2.2}$

$\: \: \: \: \: \: \: \: \: \: \: \: \: = \frac{9± \sqrt{81 - 56} }{4}$

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = \frac{9± \sqrt{25} }{4} = \frac{9±5}{4}$

On taking (+) sign,

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: x = \frac{9 + 5}{4} = \frac{14}{4} = \frac{7}{2}$

On taking (-) sign,

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: x = \frac{9 - 5}{4} = \frac{4}{4} = 1$

$∴ \: \: \: \: \: \: \: \: \: \: \: \: \: \: x = \frac{7}{2} , 1.$