Question

x(x-5)+7x+35=2(x-5)(x+5)

Answer 1

$x {}^{2} - 5x + 7x + 35 = 2(x {}^{2} - 25)$
$x {}^{2} + 2x + 35 = 2x {}^{2} - 50$
$x {}^{2} + 2x + 35 - 2x {}^{2} + 50 = 0$
$- x {}^{2} + 2x + 85 = 0$
D=4-4*(-1)*85=4+340=344
$\sqrt{d} = \sqrt{344}$
$x1 = \frac{ - 2 + \sqrt{4 + 340} }{ - 2} = 1 + \sqrt{86}$
$x2 = - \frac{ - 2 - \sqrt{4 + 344} }{ - 2} = 1 - \sqrt{86}$