\(a\cup b=\left(-2;+\infty\right)\\ a\cap b=\left(-1;2\right)\\ a\ b=(-2;-1];b\ a=[2;+\infty);C^A_R=(-\infty;-2]\cup[2;+\infty)\\ C^B_R=(-\infty;-1]\)

Khử hoàn toàn \(24\left(g\right)\) một oxit sắt bằng khí \(H_2\) , sau phản ứng thu được \(8,1\left(g\right)\) nước và m gam kim loại sắt . Tính m và tìm công thức oxit sắt 

\(=215\left(869+4+10+2+1+4\right)\\ =215.890\\ =191350\)

\(\left(3;5\right);\left(5;7\right);\left(11;13\right);\left(17;19\right);\left(29;31\right)\)

\(1,2x+3=53\\ 2x=50\\ x=50:2\\ x=25\\ 2,x-7=2017-\left(2016:2\right)\\ x-7=2017-1008\\ x-7=1009\\ x=1009+7\\ x=1016\\ 3,12\left(2x-1\right)=70-10\\ 12\left(2x-1\right)=60\\ 2x-1=5\\ 2x=5+1\\ 2x=6\\ x=3\\ 4,10\left(42-3x\right):15=250-244\\ 10\left(42-3x\right)=6.15\\ 42-3x=9\\ 3x=33\\ x=11\)

\(a,\left[{}\begin{matrix}x+2=-6x\\x+2=6x\end{matrix}\right.\)

+, \(x+2=-6x\\ x+2+6x=0\\ 7x=-2\\ x=-\dfrac{2}{7}\)

+, \(x+2=6x\\ x-6x=-2\\ -5x=-2\\ x=\dfrac{2}{5}\)

Bài này là tìm đk chứ sao lại tính nhỉ

\(a,=\sqrt{a}\left(\sqrt{b}-1\right)-\left(\sqrt{b}-1\right)\\ =\left(\sqrt{a}-1\right)\left(\sqrt{b}-1\right)\\ b,=\sqrt{x}\left(\sqrt{a}+\sqrt{b}\right)-\sqrt{y}\left(\sqrt{a}+\sqrt{b}\right)=\left(\sqrt{x}-\sqrt{y}\right)\left(\sqrt{a}+\sqrt{b}\right)\\ c,=\sqrt{a}\left(\sqrt{a}+1\right)+2\sqrt{b}\left(\sqrt{a}+1\right)\\ =\left(\sqrt{a}+2\sqrt{b}\right)\left(\sqrt{a}+1\right)\)

\(VT=\left(\sqrt{14}+\dfrac{\sqrt{6}\left(\sqrt{2}+\sqrt{5}\right)}{\sqrt{2}+\sqrt{5}}\right).\sqrt{5-\sqrt{2}1}\\ =\left(\sqrt{14}+\sqrt{6}\right).\sqrt{5-\sqrt{21}}\\ =\sqrt{70-14\sqrt{21}}+\sqrt{30-6\sqrt{21}}\\ =\sqrt{\left(7-\sqrt{21}\right)^2}+\sqrt{\left(3-\sqrt{21}\right)^2}\\ =\left|7-\sqrt{21}\right|+\left|3-\sqrt{21}\right|\\ =7-\sqrt{21}+\sqrt{21}-3\\ =4=VP\)

\(\dfrac{9}{11};\dfrac{7}{9};\dfrac{5}{7};\dfrac{3}{5};\dfrac{1}{3}\)