12 phần 25 trừ cho 14 phần 5 bằng bao nhiêu

8==D LOL

Có: \(\dfrac{7}{6}\times\dfrac{1}{2}+\dfrac{7}{6}\times\dfrac{3}{4}+\dfrac{7}{6}+\dfrac{15}{4}\)

\(=\dfrac{7}{6}\times\left(\dfrac{1}{2}+\dfrac{3}{4}+1\right)+\dfrac{15}{4}\)

\(=\dfrac{7}{6}\times\dfrac{9}{4}+\dfrac{15}{4}\)

\(=\dfrac{63}{24}+\dfrac{90}{24}=\dfrac{51}{8}\)

7/6 × 1/2 + 7/6 × 3/4 + 7/6 × 15/4

= 7/6 × (1/2 + 3/4 + 15/4)

= 7/4 × (2/4 + 3/4 + 15/4)

= 7/4 × 5

= 35/4

3 x \(\frac{4}{11}\) = \(\frac{3}{1}\) x \(\frac{4}{11}\) = \(\frac{12}{11}\)

1 : \(\frac{5}{4}\) = \(\frac{1\times4}{5}\) = \(\frac{4}{5}\)

\(\frac{4}{5}\) x \(\frac{6}{7}\) + \(\frac{2}{3}\) = \(\frac{24}{35}\) + \(\frac{2}{3}\) = \(\frac{142}{105}\)

\(\frac{3}{4}\) + \(\frac{1}{2}\) : \(\frac{5}{6}\) = \(\frac{3}{4}\) + \(\frac{1}{2}\) x \(\frac{6}{5}\) = \(\frac{3}{4}\)+ \(\frac{6}{10}\) \(\frac{27}{20}\)

\(\frac{3}{4}\)+ \(\frac{1}{2}\) = \(\frac{3}{4}\) + \(\frac{2}{4}\)= \(\frac{5}{4}\)

bài 4:so sánh

5/2 lớn hơn 3/7

4/3 lớn hơn,3/2 lớn hơn 

bài 6:rút gọn các phân số sau:

3/9=1/3      9/12=3/4          8/18=4/9         60/36=10/6         17/34=1/2              17/51=1/3           35/100=7/20           25/100=1/4                  8/1000=1/125                 24/30=4/5           18/54=1/3           72/42=12/7

đay nhé mk chưa làm hết đc bn viết liền quá mk nhìn khó mà mk hỏi bài 7 là nhân hay cộng vậy?

4 phần 5 trừ 11 phần 5 =

1 + 1 = 2

2 + 2 = 4

3 + 3 = 6

4 + 4 = 8

5 + 5 = 10

\(\frac{5}{6}=\frac{x-1}{x}\left(đk:x\ne0\right)\)

\(< =>5x=6\left(x-1\right)< =>5x=6x-6\)

\(< =>6x-5x=6< =>x=6\left(tmđk\right)\)

\(\frac{1}{2}=\frac{x+1}{3x}\left(đk:x\ne0\right)\)

\(< =>3x=2\left(x+1\right)< =>3x=2x+2\)

\(< =>3x-2x=2< =>x=2\left(tmđk\right)\)

\(\frac{3}{x+2}=\frac{5}{2x+1}\left(đk:x\ne-2;-\frac{1}{2}\right)\)

\(< =>3\left(2x+1\right)=5\left(x+2\right)< =>6x+3=5x+10\)

\(< =>6x-5x=10-3< =>x=7\left(tmđk\right)\)

\(\frac{5}{8x-2}=-\frac{4}{7-x}\left(đk:x\ne\frac{1}{4};7\right)\)

\(< =>\frac{5}{8x-2}=\frac{4}{x-7}< =>5\left(x-7\right)=4\left(8x-2\right)\)

\(< =>5x-35=32x-8< =>32x-5x=-35+8\)

\(< =>27x=-27< =>x=-1\)

\(\frac{4}{3}=\frac{2x-1}{3}< =>4.3=\left(2x-1\right).3\)

\(< =>12=6x-3< =>6x=12+3\)

\(< =>6x=15< =>x=\frac{15}{6}=\frac{5}{2}\)

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

\(< =>8x-4=9x+3< =>9x-8x=-4-3\)

\(< =>9x-8x=-7< =>x=-7\)

\(\frac{4}{x+2}=\frac{7}{3x+1}\left(đk:x\ne-2;-\frac{1}{3}\right)\)

\(< =>4\left(3x+1\right)=7\left(x+2\right)< =>12x+4=7x+14\)

\(< =>12x-7x=14-4< =>5x=10\)

\(< =>x=\frac{10}{5}=2\left(tmđk\right)\)

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

\(< =>-3\left(2-2x\right)=4\left(x+1\right)< =>-6+6x=4x+4\)

\(< =>6x-4x=4+6< =>2x=10\)

\(< =>x=\frac{10}{2}=5\left(tmđk\right)\)

\(\frac{x+1}{3}=\frac{3}{x+1}\left(đk:x\ne-1\right)\)

\(< =>\left(x+1\right)\left(x+1\right)=3.3\)

\(< =>x^2+2x+1=9< =>x^2+2x+1-9=0\)

\(< =>x^2+2x-8=0< =>x^2-2x+4x-8=0\)

\(< =>x\left(x-2\right)+4\left(x-2\right)=0< =>\left(x+4\right)\left(x-2\right)=0\)

\(< =>\orbr{\begin{cases}x+4=0\\x-2=0\end{cases}< =>\orbr{\begin{cases}x=-4\\x=2\end{cases}}}\left(tmđk\right)\)

a, \(\frac{5}{6}=\frac{x-1}{x}\Leftrightarrow5x=6x-6\Leftrightarrow-x=-6\Leftrightarrow x=6\)

b, \(\frac{1}{2}=\frac{x+1}{3x}\Leftrightarrow3x=2x+2\Leftrightarrow x=2\)

c, \(\frac{3}{x+2}=\frac{5}{2x+1}\)ĐKXĐ : \(x\ne-2;-\frac{1}{2}\)

\(\Leftrightarrow6x+3=5x+10\Leftrightarrow x=7\)

em nên gõ công thức trực quan để đề bài rõ ràng nhé

Bài 1 :Bỏ dấu ngoặc

2007-(7-3+4)

= 2007 -7+3-4

= 1999

6+[(-5) + 4 - 1 ]

= 6-5+4-1

=4

5-[(-6+8-2]

= 5+6-8+2

=5

-10+(7-3+1)

= -10 +7-3+1

= -5

Bài 3 Tìm x

\(\dfrac{1}{3} = \dfrac{x}{6}\)

\(<=> x= \dfrac{1.6}{3}\)

\(<=> x=2\)