Bài 5:
(-6).3=2.(-9)
→$\frac{-6}{-9}$ = $\frac{3}{2}$
(-12).(-3)=(-9).(-4)
→$\frac{-12}{-4}$ = $\frac{-3}{-9}$
Bài 6:Điền số
$\frac{-5}{9}$ = $\frac{10}{-18}$
$\frac{12}{-8}$ = $\frac{9}{6}$
$\frac{-46}{14}$ = $\frac{-23}{7}$
Bài 7:Tìm x,y,z
a,$\frac{x}{5}$ = $\frac{-12}{20}$
→ $\frac{-12.5}{20}$
→ -3
Vậy x = -3
b,$\frac{2}{y}$= $\frac{11}{-66}$
→$\frac{2.(-66)}{11}$
→ -12
Vậy y = -12
c,$\frac{-3}{6}$ = $\frac{x}{-2}$ = $\frac{-z}{24}$
→$\frac{-3}{6}$ = $\frac{x}{-2}$ ⇔$\frac{-3.(-2)}{6}$ =1
→$\frac{1}{-2}$ = $\frac{-18}{y}$ ⇔$\frac{-18.(-2)}{1}$ =36
→$\frac{-18}{36}$ = $\frac{-z}{24}$ ⇔$\frac{-18.24}{36}$ = -12
Vậy x = 1
y = 36
z = -12
