\(\dfrac{7}{3}+\dfrac{1}{2}-\dfrac{-3}{70}.\\ =\dfrac{7}{3}+\dfrac{1}{2}+\dfrac{3}{70}.\\ =\dfrac{17}{6}+\dfrac{3}{70}=\dfrac{302}{105}.\\ \dfrac{5}{12}-\dfrac{3}{-16}+\dfrac{3}{4}.\\ =\dfrac{5}{12}+\dfrac{3}{16}+\dfrac{3}{4}.\\ =\dfrac{29}{48}+\dfrac{3}{4}=\dfrac{65}{48}.\)

Câu 3: Điền vào 3 số tiếp theo của dãy số:

\(\text{a) 3, 6, 11, 18, 27,}\) \(38;51;66.\)

\(\text{b) 4, 9, 19, 39, 79,}\) \(159;319;639.\)

\(\text{c) 1, 2, 3, 5, 8, 13,}\) \(21;34;55.\)

\(\left(x\ne2;-1\right).\\ PT\Leftrightarrow\dfrac{x+10+3\left(x-2\right)+2\left(x+1\right)}{\left(x-2\right)\left(x+1\right)}=1.\\ \Leftrightarrow\dfrac{x+10+3x-6+2x+2}{\left(x-2\right)\left(x+1\right)}=1.\\ \Leftrightarrow\dfrac{6x+6}{\left(x-2\right)\left(x+1\right)}=1.\\ \Leftrightarrow\dfrac{6\left(x+1\right)}{\left(x-2\right)\left(x+1\right)}=1.\\ \Leftrightarrow\dfrac{6}{x-2}-1=0.\\ \Leftrightarrow\dfrac{6-x+2}{x-2}=0.\\ \Rightarrow8-x=0.\\ \Leftrightarrow x=8\left(TM\right).\)