CHÚC BẠN HỌC TỐT!!!
Trả lời:
$a,4(x+3)-2x=1$
$⇔4x+12-2x=1$
$⇔2x=-11$
$⇔x=-\dfrac{11}{2}$
Vậy `S={-11/2}`.
$b,x-\dfrac{3}{5}=1+\dfrac{2x}{3}=6$
$⇔\dfrac{15x-9+15+10x}{15}=6$
$⇔25x+6=90$
$⇔x=\dfrac{84}{25}$
Vậy `S={84/25}`.
$c,(x+4)(3x-5)=0$
$⇔\left[ \begin{array}{l}x+4=0\\3x-5=0\end{array} \right.⇔\left[ \begin{array}{l}x=-4\\x=\dfrac{5}{3}\end{array} \right.$
Vậy `S={-4;5/3}`.
$d,$ ĐKXĐ: $x\neq ±2$
$\dfrac{x-1}{x+2}-\dfrac{x}{x-2}=\dfrac{7x-6}{4-x^2}$
$⇔\dfrac{(x-1)(x-2)}{x^2-4}-\dfrac{x(x+2)}{x^2-4}=\dfrac{7x-6}{4-x^2}$
$⇔\dfrac{x^2-3x+2-x^2-2x}{x^2-4}=\dfrac{6-7x}{x^2-4}$
$⇔-5x+2=6-7x$
$⇔2x=4$
$⇔x=2\,(L)$
Vậy phương trình vô nghiệm.
