Question

solve the following equation by quadratic formula 5x {}^{2} - 8x - 4 = 05x 2 −8x−4=0 ​

Answer 1

Answer:

${5x}^{2} - 8x - 4 = 0$

${5x}^{2} - (10 - 2)x - 4 = 0$

${5x}^{2} - 10x + 2x - 4 = 0$

$5x(x - 2) + 2(x - 2) = 0$

$(5x + 2)(x - 2) = 0$

$(5x + 2) = 0 \: and \: (x - 2) = 0$

x = -2/5 and x = 2

Ans. -2/5, 2

Hope it helps.

Answer 2

$= 5 {x}^{2} - 8x - 4$

$= 5 {x}^{2} - (10 - 2)x - 4$

$= 5 {x}^{2} - 10x + 2x - 4$

$= 5x(x - 2) + 2(x - 2)$

$=( 5x + 2)(x - 2)$

$5x + 2 = 0$

$5x = - 2$

$x = \frac{ - 2}{5}$

$x - 2 = 0$

$x = 2$