\(\frac{72-x}{3}=\frac{x-18}{5}\)
\(\Rightarrow\frac{\left(72-x\right).5}{15}=\frac{3\left(x-18\right)}{15}\)
\(\Rightarrow\left(72-x\right).5=3\left(x-18\right)\)
\(\Rightarrow360-5x=3x-54\)
\(\Rightarrow-3x-5x=-360-54\)
\(\Rightarrow-8x=-414\)
\(\Rightarrow x=51,75\)
+) Vì \(\frac{72-x}{3}=\frac{x-18}{5}\)
\(\Rightarrow5\left(72-x\right)=3\left(x-18\right)\)
\(5.72-5x=3x-3.18\)
\(360-5x=3x-54\)
\(-5x-3x=-54-360\)
\(-8x=-414\)
\(x=-414:\left(-8\right)\)
\(x=51,75\)
Vậy x = 51,75
\(\frac{72-x}{3}=\frac{x-18}{5}\)
\(\Leftrightarrow5\left(7x-2\right)=3\left(x-18\right)\)
\(\Leftrightarrow360-5x=3x-54\)
\(\Leftrightarrow360=3x-54+5x\)
\(\Leftrightarrow360=8x-54\)
\(\Leftrightarrow8x-54=360\) (chuyển vế)
\(\Leftrightarrow8x=360+54\)
\(\Leftrightarrow8x=414\)
\(\Leftrightarrow x=\frac{414}{8}=\frac{207}{4}\)
\(\Rightarrow x=\frac{207}{4}\)
\(\frac{72-x}{3}=\frac{x-18}{5}\)
<=> 360 - 5x = 3x - 54
<=> -8x = -414
<=> x = \(\frac{207}{4}\)
5(72-x)=3(x-18)
360 - 5x = 54 - 3x
-5x +3x = 54-360
-2x = -306
x = -306 : -2 = 153
\(\frac{72-x}{3}=\frac{x-18}{5}\)
\(\frac{5\left(72-x\right)}{3.5}=\frac{3\left(x-18\right)}{5.3}\)
\(\frac{360-5x}{15}=\frac{3x-54}{15}\)
\(\Rightarrow360-5x=3x-54\)
\(\Rightarrow360+54=3x+5x\)
\(\Rightarrow414=8x\)
\(\Rightarrow x=\frac{414}{8}=\frac{212}{4}=\frac{106}{2}=\frac{53}{1}=53\)
\(\Rightarrow x=53\)
