Question

[lê nhật duẫn]

bài 2 : thực hiện phép tính

a. \(\frac{5x+10}{4x-8}.\frac{4-2x}{x+2}\)

b. \(\frac{12x}{5y^3}.\frac{15y^4}{8x^3}\)

c.\(\frac{4y^2}{11x^4}.\left(-\frac{3x^2}{8y}\right)\)

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

e.\(\frac{5x+10}{4x-8}.\frac{4-2x}{x+2}\)

f.\(\frac{x^2-36}{2x+10}.\frac{3}{6-x}\)

g.\(\frac{x^2-9y^2}{x^2y^2}.\frac{3xy}{2x-6}\)

h.\(\frac{1-4x^2}{x^2+4x}:\frac{2-4x}{3x}\)

i.\(\frac{a^2+ab}{b-a}:\frac{a+b}{2a^2-2b^2}\)

j.\(\frac{x+y}{y-x}:\frac{x^2+xy}{3x^2-3y^2}\)

k.\(\frac{1-4x^2}{x^2+4x}:\frac{2-4x}{3x}\)

Answer 1

[Nguyễn Ngọc Lộc]

ĐKXĐ bạn tự tìm nha : )

k, Ta có : \(\frac{1-4x^2}{x^2+4x}:\frac{2-4x}{3x}=\frac{\left(1-2x\right)\left(1+2x\right)}{x\left(x+4\right)}.\frac{3x}{2\left(1-2x\right)}\)

\(=\frac{3x\left(1-2x\right)\left(1+2x\right)}{2x\left(x+4\right)\left(1-2x\right)}=\frac{3\left(1+2x\right)}{2\left(x+4\right)}\)

j, Ta có : \(\frac{x+y}{y-x}:\frac{x^2+xy}{3x^2-3y^2}=\frac{x+y}{y-x}:\frac{x\left(x+y\right)}{3\left(x^2-y^2\right)}=\frac{x+y}{y-x}.\frac{3\left(x-y\right)\left(x+y\right)}{x\left(x+y\right)}\)

\(=\frac{3\left(x-y\right)\left(x+y\right)}{x\left(y-x\right)}=\frac{3\left(x-y\right)\left(x+y\right)}{-x\left(x-y\right)}=\frac{-3\left(x+y\right)}{x}\)

i, Ta có : \(\frac{a^2+ab}{b-a}:\frac{a+b}{2a^2-2b^2}=\frac{a\left(a+b\right)}{-\left(a-b\right)}:\frac{a+b}{2\left(a^2-b^2\right)}=\frac{a\left(a+b\right)}{-\left(a-b\right)}.\frac{2\left(a-b\right)\left(a+b\right)}{a+b}\)

\(=\frac{2a\left(a+b\right)\left(a-b\right)}{-\left(a-b\right)}=-2a\left(a+b\right)\)

h, = k,

f, Ta có : \(\frac{x^2-36}{2x+10}.\frac{3}{6-x}=\frac{\left(x-6\right)\left(x+6\right)}{2\left(x+5\right)}.\frac{-3}{x-6}=\frac{-3\left(x-6\right)\left(x+6\right)}{2\left(x+5\right)\left(x-6\right)}=\frac{-3\left(x+6\right)}{2\left(x+5\right)}\)

Answer 2

[💋Amanda💋]

https://i.imgur.com/1LeIfCN.jpg