Question

a)

x + y = 20
x - y = 8


b)

2x + 3y = 19
3x - 2y = -6

Answer 1

adiçao A)x+y=20
               x-y=8
               2x=12
              
             x=12/2
               x=6
6+y=20
y=20-6
y=14
s=x=6,y=14
 
B)2x+3y=19(vezes 3)
    3x - 2y=-6(vezes -2)         
                                               
    6x+9y=57          
    6x+4y=12

         5y=45
         y=45/5
         y=9

(2x+27=19
2x=19-27
2x=8
x=8/2
x=4

s=x=4,y=9