Đáp án:
$a) 3x+3=5x-17$
$=> 3x-5x=-17-3$
$=> -2x=-20$
$=> x=10$
Vậy $S=${$10$}
$b)$ $\dfrac{3x+1}{3}$ $+ 1 =$ $\dfrac{2x-5}{4}$ $-$ $\dfrac{1-4x}{12}$
$=> 4(3x+1)+12=3(2x-5)-1+4x$
$=> 12x+4+12=6x-15-1+4x$
$=> 12x-6x-4x=-15-1-4-12$
$=> 2x=-32$
$=> x=-16 $
Vậy $S=${$-16$}
$c) (x-9)(x²-25)=0$
$=> x-9=0$ hoặc $x²-25=0$
$=> x=9$ hoặc $x²=25$
$=> x=9$ hoặc $x²=±5²$
$=> x=9$ hoặc $x=±5$
Vậy $S=${$9;5;-5$}
$d) (1–2x) . (3x+7)=1–4x²$
$=> 3x+7-6x²-14x-1+4x²=0$
$=> -2x²-11x+6=0$
$=> -2x²-12x+x+6=0$
$=> -2x(x+6)+(x+6)=0$
$=> (x+6)(-2x+1)=0$
$=> x+6=0$ hoặc $-2x+1=0$
$=> x=-6$ hoặc $x=0,5$
Vậy $S=${$-6;0,5$}
BẠN THAM KHẢO NHA!!!
