Đáp án:12)Đúng
13)$x=\frac{1}{18}$
14)$x=\frac{1}{16}$
15)x=10
16$x=\frac{197}{11}$
Giải thích các bước giải:
$12)\frac{x-4}{3}=\frac{x-1}{3}-1$
$⇒x-4=x-1-3⇔ -4=-4$ (đúng)
$13)3(x-2)+15=5(2-3x)$
$⇔3x-6+15=10-15x⇔ 18x=1⇔ x=\frac{1}{18}$
$14)2(x-5)-3(2x-1)=4(3x-2)+2$
$⇔2x-10-6x+3=12x-8+2$
$⇔16x=1⇔x=\frac{1}{16}$
$15)\frac{5x-4}{2}=\frac{16x+1}{7}$
$⇒7(5x-4)=2(16x+1)⇔ 35x-28=32x+2$
$⇔3x=30⇔ x=10$
$16)\frac{3(x-11)}{4}=\frac{3(x+1)}{5}-\frac{2(2x-5)}{10}$
$⇒15(x-11)=12(x+1)-4(2x-5)$
$⇔15x-165=12x+12-8x+20$
$⇔11x=197⇔ x=\frac{197}{11}$
