Question

Tính : \(\dfrac{1}{x+2}+\dfrac{1}{\left(x+2\right)\left(4x+7\right)}\)

Answer 1

\(=\dfrac{4x+8}{\left(x+2\right)\left(4x+7\right)}=\dfrac{4}{4x+7}\)

Answer 2

\(\dfrac{1}{x+2}+\dfrac{1}{\left(x+2\right)\left(4x+7\right)}\\ =\dfrac{4x+7}{\left(x+2\right)\left(4x+7\right)}+\dfrac{1}{\left(x+2\right)\left(4x+7\right)}\\ =\dfrac{4x+7+1}{\left(x+2\right)\left(4x+7\right)}\\ =\dfrac{4x+8}{\left(x+2\right)\left(4x+7\right)}\\ =\dfrac{4\left(x+2\right)}{\left(x+2\right)\left(4x+7\right)}\\ =\dfrac{4}{4x+7}\)