Đáp án:
Giải thích các bước giải:
bài 2:
a, 7x+2=3x-4
⇔7x-3x=-2-4
⇔4x=-6
⇔x=-3/2
Vậy...
b,-Đkxđ:x$\neq$ -1;x$\neq$3
$\frac{3x+1}{x+1}$ -$\frac{2x-5}{x-3}$=$\frac{-4}{(x+1)(x-3)}$
⇔$\frac{3x²-9x+x-3-2x²-2x+5x+5}{(x+1)(x-3)$= $\frac{-4}{(x+1)(x-3)}$
⇔3x²-9x+x-3-2x²-2x+5x+5=-4
⇔x²-5x+6=0
⇔x²-2x-3x+6=0
⇔x(x-2)-3(x-2)=0
⇔(x-3)(x-2)=0
⇔\(\left[ \begin{array}{l}x-3=0\\x-2=0\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=3(loại)\\x=2(t/m)\end{array} \right.\)
Vậy...
c, $\frac{2x-1}{6}$+$\frac{x+1}{3}$ $\leq$ $\frac{3x-8}{8}$
⇔$\frac{8x-4+8x+8}{24}$ $\leq$ $\frac{9x-24}{24}$
⇔8x-4+8x+8≤9x-24
⇔16x-9x≤4-8-24
⇔7x≤-28
⇔ 7x÷7≤-28÷7
⇔x≤-4
Vậy...
