chupj ngang kiaf

đầu tiên là chữ khá đẹp

thứ 2 là mk gãy cổ rùi

Bài 2: 

Gọi tử là x

Mẫu là x+6

Theo đề, ta có:

\(\dfrac{x+3}{x+5}=\dfrac{4}{5}\)

=>5x+15=4x+20

=>x=5

1824 : 32 = 57

15 622 : 73 = 214

1824 : 32 = 57

15622 : 73 = 214

a: \(=3+\dfrac{4}{9}\cdot\dfrac{25}{7}\cdot\dfrac{7}{25}\cdot\dfrac{9}{4}-\dfrac{7}{25}\)

=3+1-7/25=4-7/25=93/25

b: \(=\dfrac{5}{10}\cdot\dfrac{7}{14}\cdot\dfrac{9}{18}\cdot\dfrac{11}{22}\cdot\dfrac{13}{26}\cdot\dfrac{15}{30}\)

=1/2*1/2*1/2*1/2*1/2*1/2

=1/64

Bạn không bíết làm à ?

tham khảo link này ik bn ơi 

https://booktoan.com/giai-bai-tap-toan-6.html

kb nhak

Thanks <3

Bài 3:

a: \(x\left(x-7\right)+2x^2=\left(x+1\right)\left(3x-2\right)\)

=>\(x^2-7x+2x^2=3x^2-2x+3x-2\)

=>\(3x^2+x-2=3x^2-7x\)

=>x-2=-7x

=>8x=2

=>\(x=\frac28=\frac14\)

b: \(\left(5x-3\right)\left(2x+1\right)-\left(2x-1\right)^2+4=0\)

=>\(\left(5x-3\right)\left(2x+1\right)-\left\lbrack\left(2x-1\right)^2-4\right\rbrack=0\)

=>(5x-3)(2x+1)-(2x-1-2)(2x-1+2)=0

=>(5x-3)(2x+1)-(2x+1)(2x-3)=0

=>(2x+1)(5x-3-2x+3)=0

=>3x(2x+1)=0

=>x(2x+1)=0

=>\(\left[\begin{array}{l}x=0\\ 2x+1=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=0\\ x=-\frac12\end{array}\right.\)

c: \(4x^2-9=\left(3-2x\right)\left(x+2\right)\)

=>\(\left(2x-3\right)\left(2x+3\right)+\left(2x-3\right)\left(x+2\right)=0\)

=>(2x-3)(2x+3+x+2)=0

=>(2x-3)(3x+5)=0

=>\(\left[\begin{array}{l}2x-3=0\\ 3x+5=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=\frac32\\ x=-\frac53\end{array}\right.\)

a) Tìm x

\(\frac{8}{5}+x=\frac{17}{3}\)

\(\Rightarrow x=\frac{17}{3}-\frac{8}{5}\)

\(\Rightarrow x=\frac{61}{15}\)

\(x-\frac{17}{14}=\frac{80}{11}\)

\(\Rightarrow x=\frac{80}{11}+\frac{17}{14}\)

\(\Rightarrow x=\frac{1307}{154}\)

b) Tính nhanh

\(52\times95+47\times95+95\)

\(=95\times\left(52+47+1\right)\)

\(=95\times100\)

\(=9500\)

\(a.\)\(\frac{8}{5}+x=\frac{17}{3}\)

\(\Leftrightarrow x=\frac{17}{3}-\frac{8}{5}\)

\(\Leftrightarrow x=\frac{85}{15}-\frac{24}{15}\)

\(\Leftrightarrow x=\frac{61}{15}\)

\(x-\frac{17}{14}=\frac{80}{11}\)

\(\Leftrightarrow x=\frac{80}{11}+\frac{17}{14}\)

\(\Leftrightarrow x=\frac{1120}{154}+\frac{187}{154}\)

\(\Leftrightarrow x=\frac{1307}{154}\)

\(b.\)Cách tính nhanh nhé:

\(52.95+47.95+95\)

\(=52.95+47.95+95.1\)

\(=95.\left(52+47+1\right)\)

\(=95.100\)

\(=9500\)

~ Rất vui vì giúp đc bn ~

\(\Delta'=16-\left(3m+1\right)\ge0\Rightarrow m\le5\)

Theo hệ thức Viet: \(\left\{{}\begin{matrix}x_1+x_2=-8\\x_1x_2=3m+1\end{matrix}\right.\)

Kết hợp điều kiện đề bài ta được: \(\left\{{}\begin{matrix}x_1+x_2=-8\\5x_1-x_2=2\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}x_1+x_2=-8\\6x_1=-6\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}x_1=-1\\x_2=-7\end{matrix}\right.\)

Thế vào \(x_1x_2=3m+1\)

\(\Rightarrow\left(-1\right).\left(-7\right)=3m+1\)

\(\Rightarrow m=2\) (thỏa mãn)

Đăng 1 bài 1 thôi bạn

a: \(\Leftrightarrow\left(x+8-3x+7\right)\left(x+8+3x-7\right)=0\)

=>(-2x+15)(4x+1)=0

=>x=15/2 hoặc x=-1/4

b: \(\Leftrightarrow\left(x-5\right)\left(x+6-x+5\right)=0\)

=>x-5=0

hay x=5

c: \(\Leftrightarrow x^2+15x+56-x^2+6x-9=0\)

=>21x=-47

hay x=-47/21