17. What is the value of two numbers if their sum is 120 and their difference is 140?
17. What is the value of two numbers if their sum is 120 and their difference is 140?
\(\begin{array}{|rcll|} \hline \mathbf{a+b} &=& \mathbf{120} \\ \mathbf{b} &=& \mathbf{120 -a} \qquad (1) \\\\ \mathbf{a-b} &=& \mathbf{140} \\ a-(120 -a) &=& 140 \\ 2a-120 &=& 140 \\ 2a &=& 260 \\ \mathbf{a} &=& \mathbf{130} \\\\ \mathbf{b} &=& \mathbf{120 -a} \\ b &=& \mathbf{120 -130} \\ \mathbf{b} &=& \mathbf{-10} \\ \hline \end{array}\)