Question

tính

\(\dfrac{x}{x+2}+\dfrac{7x-16}{\left(x+2\right)\left(4x-7\right)}\)

Answer 1

\(\dfrac{x}{x+2}+\dfrac{7x-16}{\left(x+2\right)\left(4x-7\right)}\)

\(=\dfrac{4x^2-7x}{\left(x+2\right)\left(4x-7\right)}+\dfrac{7x-16}{\left(x+2\right)\left(4x-7\right)}\)

\(=\dfrac{4x^2-7x+7x-16}{\left(x+2\right)\left(4x-7\right)}\)

\(=\dfrac{4x^2-16}{\left(x+2\right)\left(4x-7\right)}\)

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

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

\(=\dfrac{2x-4}{4x-7}\)