Chapter 1.1, Problem 7E

In Exercises 7-10, coefficients are given for a system of the form (2). Display the system and verify that the given values constitute a solution.

$a_{11}=1,$ $a_{12}=3$, $a_{21}=4$, $a_{22}=-1$,

$b_1=7$, $b_2=2$, $x_1=1$, $x_2=2$