Bài 1:
a) \(\Rightarrow x=\dfrac{\left(-3\right)\left(-4\right)}{5}=\dfrac{12}{5}\)
b) \(\Rightarrow x=\dfrac{10.36}{\left(-12\right)}=-30\)
c) \(\Rightarrow x=\dfrac{2,1.3}{0,7}=9\)
d) \(\Rightarrow x=\dfrac{132.\left(-7\right)}{11}=-\dfrac{12}{7}\)
e) \(\Rightarrow x=\dfrac{4.12}{30.5}=\dfrac{8}{25}\)
f) \(\Rightarrow x=\dfrac{\left(-15\right).6}{\left(-2\right).\left(-4\right)}=-\dfrac{45}{4}\)
g) \(\Rightarrow x=\dfrac{3.45}{15}=9\)
Bài 2:
a) \(\dfrac{x}{2}=\dfrac{y}{5}=\dfrac{x+y}{2+5}=\dfrac{21}{7}=3\)
\(\Rightarrow\left\{{}\begin{matrix}x=2.3=6\\y=3.5=15\end{matrix}\right.\)
b) \(\dfrac{x}{6}=\dfrac{y}{9}=\dfrac{x-y}{6-9}=\dfrac{30}{-3}=-10\)
\(\Rightarrow\left\{{}\begin{matrix}x=\left(-10\right).6=-60\\y=\left(-10\right).9=-90\end{matrix}\right.\)
\(10,\\ a,\Rightarrow x=\dfrac{-3\left(-4\right)}{5}=\dfrac{12}{5}\\ b,\Rightarrow x=\dfrac{10\cdot36}{-12}=-30\\ c,\Rightarrow x=\dfrac{2,1\cdot3}{0,7}=9\\ d,\Rightarrow x=\dfrac{132\left(-7\right)}{11}=-84\\ e,\Rightarrow x=\dfrac{4\cdot12}{30\cdot5}=\dfrac{48}{150}=\dfrac{8}{25}\\ f,\Rightarrow x=\dfrac{-15\cdot6}{\left(-2\right)\left(-4\right)}=\dfrac{-45}{4}\\ g,\Rightarrow x=\dfrac{3\cdot45}{15}=9\)
bài 1
x.5=-3.(-4)
x.5=12
x=2,4
b)
-12.x=10.36
-12.x=360
x=-30
c)
\(\dfrac{2,1}{0,7}=3=\dfrac{x}{3}\)
x=3.3
x=9
d)
\(\dfrac{11}{132}=\dfrac{1}{12}=\dfrac{-7}{x}\)
x=-7.12
x=-84
