Question

tìm x biết

a,3/4x-1/5=7/4x+11/5

b,x+1/2=8/x+1

các bạn giup mink vs nha mink ngu toán

 

Answer 1

a, \(\frac{3}{4}x-\frac{1}{5}=\frac{7}{4}x+\frac{11}{5}\)

\(\Rightarrow\frac{3}{4}x-\frac{7}{4}x=\frac{11}{5}+\frac{1}{5}\)

\(\Rightarrow-x=\frac{12}{5}\Rightarrow x=-\frac{12}{5}\)

Vậy ... 

b, \(\frac{x+1}{2}=\frac{8}{x+1}\)

\(\Rightarrow\left(x+1\right)^2=16\)

\(\Rightarrow x+1=4\)hoặc \(x+1=-4\)

\(\Rightarrow x=3\) hoặc  \(x=-5\)

Vậy ..

Answer 2

3/4x-7/4x=1/5+11/5

(3/4-7/4).x=12/5

-1.x=12/5

x=12/5:-1

x=-12/5

vậy x=-12/5

Answer 3

a,\(\frac{3}{4}x-\frac{1}{5}=\frac{7}{4}x+\frac{11}{5}\)

\(< =>\frac{3x}{4}-\frac{7x}{4}=\frac{11}{5}+\frac{1}{5}=\frac{12}{5}\)

\(< =>-\frac{4x}{4}=\frac{12}{5}< =>-x=\frac{12}{5}\)

\(< =>x=-\frac{12}{5}\)

b, \(x+\frac{1}{2}=\frac{8}{x}+1\left(đk:x\ne0\right)\)

\(< =>x-\frac{8}{x}=1-\frac{1}{2}=\frac{1}{2}\)

\(< =>\frac{x^2-8}{x}=\frac{1}{2}\)

\(< =>2x^2-16=x\)

\(< =>2x^2-x+16=0\)

\(\Delta=\left(-1\right)^2-4.2.16 < 0\)

Vô nghiệm  :V bài này sai đề