Question

 решите неравенства
а)12(-4+7x)> или равно -3х+9 
б)-2х^2+10x-12<0

Answer 1

$1); 12(-4+7x) geq -3x+9\\-48+84x+3x-9 geq 0\\87x geq 57\\x geq frac{57}{87}\\2); -2x^2+10x-12<0\\x^2-10x+6>0\\D=100-24=76=4*19\\x_1=frac{10-2sqrt{19}}{2}=5-sqrt{19}\\x_2=5+sqrt{19}$