$2y-7x+3x=2y-4x2y-7x+3x=2y-4x$

$\mathrm{0,1}{a}^2\cdot 30a^3=\mathrm{0,1}\cdot 30\cdot a^{2+3}=3\cdot a^{5}0\{,\}1a^2\backslash cdot\; 30a^3=0\{,\}1\backslash cdot\; 30\backslash cdot\; a^\{2+3\}=3\backslash cdot\; a^5$

${\left({\displaystyle \frac{1}{3}}{x}^3\right)}^2={\displaystyle \frac{1}{3^2}}{x}^{3\cdot 2}={\displaystyle \frac{1}{9}}{x}^6\backslash left(\backslash dfrac\{1\}\{3\}x^3\backslash right)^2=\backslash dfrac\{1\}\{3^2\}\backslash ,x^\{3\backslash cdot\; 2\}=\backslash dfrac\{1\}\{9\}x^6$