Đáp án:
$a,5-3x>9$
$<=>5-3x-9>0$
$<=>-4-3x>0$
$<=>-3x>4$
$<=>x< -\frac{4}{3}$
$Vậy$ $bất$ $pt$ $có$ $nghiệm:$ $S$$=${$x∈R|$ $x<$ $-$$\frac{4}{3}$}
$b,2x-10<0$
$<=>2x<10$
$<=>x<5$
$Vậy$ $bất$ $pt$ $có$ $nghiệm:$ $S=${$x∈R$|$x<5$}
$c,2x+\frac{3}{7}>x- \frac{5}{4}$
$<=>2x-x>- \frac{5}{4} -\frac{3}{7}$
$<=>x>-\frac{47}{28}$
$Vậy$ $bất$ $pt$ $có$ $nghiệm: S=${$x∈R|x>$$-$$\frac{47}{28}$}
$d,x-2<3x+1$
$<=>x-3x<1+2$
$<=>-2x<3$
$<=>x>-\frac{3}{2}$
$Vậy$ $bất$ $pt$ $có$ $nghiệm: S=${$x∈R|x>$$-$$\frac{3}{2}$}
$e,8x+2 \leq 7(x-1)$
$<=>8x+2\leq 7x-7$
$<=>8x-7x\leq -7-2$
$<=>x\leq -9$
$Vậy$ $bất$ $pt$ $có$ $nghiệm: S=${$x∈R|x$ $\leq$ $-9$}
$f,2(3x-2)<3.(4x-3+11)$
$<=>6x-4<3(4x+8)$
$<=>6x-4<12x+24$
$<=>6x-12x<24+4$
$<=>-6x<28$
$<=>x>-\frac{14}{3}$
$Vậy$ $bất$ $pt$ $có$ $nghiệm: S=${$x∈R|x>$$-$$\frac{14}{3}$}
$Chúc$ $bạn$ $học$ $tốt$$!$
$Answered$ $by$ $Mai$ $Chi$$.$
