a) \(\displaystyle {\rm{}}{x^2} + 5{{\rm{x}}^2} + ( - 3{{\rm{x}}^2}) \)
\(\displaystyle = (1 + 5 - 3).{x^2} \)
\(\displaystyle = 3{{\rm{x}}^2}\)
b) \(\displaystyle 5{\rm{x}}{y^2} + {1 \over 2}x{y^2} + {1 \over 4}x{y^2} + \left( { - {1 \over 2}} \right)x{y^2} \)
\(\displaystyle = \left( {5 + {1 \over 2} + {1 \over 4} - {1 \over 2}} \right)x{y^2} \)
\(\displaystyle = {{21} \over 4}x{y^2}\)
c) \(\displaystyle 3{{\rm{x}}^2}{y^2}{z^2} + {{\rm{x}}^2}{y^2}{z^2} \)
\(\displaystyle = \left( {3 + 1} \right){{\rm{x}}^2}{y^2}{z^2} \)
\(\displaystyle = 4{{\rm{x}}^2}{y^2}{z^2}\)
