Question

Giải pt a/ x-2/3 - x-4/5 = x-5/6

b/ ( 3x - 2 )^2 = ( 2 - 3x ) . ( 4x + 5 )

Answer 1

\(a;x-\frac23-x-\frac45=x-\frac56\) \(\Rightarrow-\frac{22}{15}=x-\frac56\Rightarrow x=-\frac{22}{15}+\frac56=-\frac{19}{30}\)

\(b;\left(3x-2\right)^2=\left(2-3x\right)\cdot\left(4x+5\right)\Rightarrow\left(3x-2\right)^2=-\left(3x-2\right)\cdot\left(4x+5\right)\)

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

\(\Rightarrow\left(3x-2\right)\cdot\left(7x+3\right)=0\Rightarrow\left[\begin{array}{l}x=\frac23\\ x=-\frac37\end{array}\right.\)