1)3x^2+9x-2x-6≥2x^2+12
x^2+7x-18≥0
D=49-4*1*(-18)=121
x1=(-7+11)/2=4/2=2
x2=(-7-11)/2=-18/2=-9
Проверка:
(6-2)(2+3)=2*4+12
20=20
(-27-2)(-9+3)=2*81+12
174=174
X∈(-∞;-9)∪(2;∞)
2)5(√6+1)-5(√6-1)/(√6-1)(√6+1)=(5√6+5-5√6+5)/(6-√6+1)=10/7-√6=10/4.55=2.198