Question

resolver pela regra de cramer
3x+y=9
2x+3y=13

Answer 1

Δ = $\left[\begin{array}{ccc}3&1\\2&3\end{array}\right]$ = 9 - 2 = 7

Δy = $\left[\begin{array}{ccc}3&9\\2&13\\\end{array}\right]$ = 39 -18 =21

Δx= $\left[\begin{array}{ccc}9&1\\13&3\\\end{array}\right]$ = 27 -13 = 14

Logo :   x =$\frac{14}{7}$ = 2
             y=$\frac{21}{7}$ = 3

Assim :  S ={ (2,3)}