Question

{x+y=7
{xy=12 como resolver​

Answer 1

$x + y = 7 \\ xy = 12$

$y = 7 - x \\ x( 7 - x) = 12$

$x \times x = {x}^{2}$

$x \times 7 = 7x$

${x}^{2} - 7x = 12$

∆=b²-4ac

∆=(-7)²-4.1.12

∆=(-7).(-7)-4.12

∆=49-48

∆=1

$- b \frac{ + }{} \sqrt{1} \\ \sqrt{1 } = 1$

x1= -7+1 x2=-7-1

x1= -6 x2=-8