Question

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

Answer 1

$\mathbf{ \large{It \: is \: not \: mentioned \: whether \: solution should \: be \: done \: by \: using \: quadratic \: equation \: or \: not, \: this \: solution \: is by \: factorization \: method \: }}$



5x² - 4 = 8x

=> 5x² - 8x - 4 = 0

=> 5x² - ( 10 - 2 )x - 4 = 0

=> 5x² - 10x + 2x - 4 = 0

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

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

=> x - 2 = 0 or 5x + 2 = 0

=> x = 2 or 5x = –2

$= > x = 2 \: \: \: or \: \: \: x = - \frac{2}{5}$