Question

х^2+2х-15>0, х^2>равно36

Answer 1

${x}^{2} + 2x - 15 > 0$
${x}^{2} + 2x - 15 = 0$
$d = {b}^{2} - 4ac = 4 + 45 = 49 = 7$
$x1 = - b + d \div 2 = - 2 + 7 \div 2 = 2.5$
$x2 = - b - d \div 2 = - 2 - 7 \div 2 = 4.5$
второе:
${x}^{2} \geqslant 36$
$x \geqslant + - 6$