Question

resolva cada sistema de equações.
a+2b=9
3a-2b=3

Answer 1

$\left \{ {{a + 2b =9} \atop {3a - 2b = 2}} \right. \\ \\ 4a = 11 \\ a = \frac{11}{4} \\ \\ \frac{11}{4} + 2b = 9 \\ 11 + 8b + 36 \\ 8b = 25 \\ b = \frac{25}{8} \\ \\ S = { 11/4 ; 25/8}$

Answer 2

{a+2b=9
3a-2b=3
4a=12
a=12:4
a=3

3*3-2b=3
9-2b=3
-2b=3-9
-2b=-6
b=-6:-2
b=-8

S={(3,-8)}