Solve the System $$\left\{ \begin{array} { l } x + y = 1 \\x + y = - 3\end{array} \right.$$

Q80: Verify that the values of the

Q81: Find the inverse of the matrix.<br>-

Q82: Write the augmented matrix for the

Q83: Use the elimination method to solve

Q84: Use the properties of determinants to

Q86: Write the word or phrase that

Q87: Solve the problem.<br>-A person at the

Q88: Find the inverse of the matrix.<br>-

Q89: Solve the system of equations using

Q90: Verify that the values of the