Bài 1:
a: \(x:27=-2:3,6\)
=>\(\dfrac{x}{27}=\dfrac{-5}{9}\)
=>\(x=-\dfrac{5}{9}\cdot27=-15\)
b: ĐKXĐ: x<>-1/2
\(\dfrac{2x+1}{-27}=\dfrac{-3}{2x+1}\)
=>\(\left(2x+1\right)^2=\left(-27\right)\cdot\left(-3\right)=81\)
=>\(\left[{}\begin{matrix}2x+1=9\\2x+1=-9\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}x=4\left(nhận\right)\\x=-5\left(nhận\right)\end{matrix}\right.\)
Bài 2:
a: \(Q\left(x\right)=-3x^4+4x^3+2x^2+\dfrac{2}{3}-3x-2x^4-4x^3+8x^4+1+3x\)
\(=\left(-3x^4-2x^4+8x^4\right)+\left(4x^3-4x^3\right)+2x^2+\left(-3x+3x\right)+\dfrac{2}{3}+1\)
\(=3x^4+2x^2+\dfrac{5}{3}\)
b: \(3x^4>=0\forall x;2x^2>=0\forall x\)
Do đó: \(3x^4+2x^2>=0\forall x\)
=>\(3x^4+2x^2+\dfrac{5}{3}>=\dfrac{5}{3}>0\forall x\)
=>Q(x) không có nghiệm
