ok... we'll do the same here, elimination
g = carbs in one glass of milk
b = carbs in a snack bar
[tex]\bf \begin{array}{llcll}
4g+3b=93&\implies &4g+3b=93\\
2g+4b=74&\boxed{-2}\implies &-4g-8b=-148\\
&&----------\\
&&0-5b=-55
\end{array}
\\\\\\
-5b=-55\implies b=\cfrac{-55}{-5}\implies \boxed{b=11}\\\\
-------------------------------\\\\
\textit{let's plug that in either, hmm the second equation}\\\\
2g+4(11)=74\implies 2g+44=74\implies 2g=74-44
\\\\\\
2g=30\implies g=\cfrac{30}{2}\implies \boxed{g=15}[/tex]
in this, we can simply multiply by -2 at the bottom to get a -4g, and thus "eliminate" the g-variable
