Question

Thực hiện phép tính:

a) (9x2 phần 17y5) - (34y3 phần 45x)

b) (4x phần x+2) - (3x phần x-2) + (12 phần x2-4)

Viết rõ các bước dùm mình nha!

Answer 1

b) \(\frac{4x}{x+2}-\frac{3x}{x-2}+\frac{12}{x^2-4}\)

\(=\frac{4x}{x+2}-\frac{3x}{x-2}+\frac{12}{\left(x-2\right).\left(x+2\right)}\)

\(=\frac{4x.\left(x-2\right)}{\left(x-2\right).\left(x+2\right)}-\frac{3x.\left(x+2\right)}{\left(x-2\right).\left(x+2\right)}+\frac{12}{\left(x-2\right).\left(x+2\right)}\)

\(=\frac{4x^2-8x}{\left(x-2\right).\left(x+2\right)}-\frac{3x^2+6x}{\left(x-2\right).\left(x+2\right)}+\frac{12}{\left(x-2\right).\left(x+2\right)}\)

\(=\frac{4x^2-8x}{\left(x-2\right).\left(x+2\right)}+\frac{-\left(3x^2+6x\right)}{\left(x-2\right).\left(x+2\right)}+\frac{12}{\left(x-2\right).\left(x+2\right)}\)

\(=\frac{4x^2-8x-3x^2-6x+12}{\left(x-2\right).\left(x+2\right)}\)

\(=\frac{x^2-14x+12}{\left(x-2\right).\left(x+2\right)}\)

Chúc bạn học tốt!