Here is a start:\(\displaystyle \left\{ \begin{array}{l}3(5a)-4(3a)=a+4\\3d-4(5d)=68\end{array} \right.\)Hello, in my homework I came across this problem:
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The text didn't really go over how to solve it and I'm finding it difficult to understand. Is there anyone who can explain how to get the answer?