Question

resolva os sistemas de adição
A) X+Y=-3
3X-Y=1

B) X+2Y=12
3X-Y=22

Answer 1

a)
x+y = 3
+3x-y= 1
______
4x = 4
x= 1, logo, 1+y=3 -> y=2


b)
x+2y = 12
3x-y=22 ×(2 )=> pra facilitar

x+2y = 12
+6x-2y = 44
_________
7x = 56
x= 8, logo, 8+ 2y = 12 -> 2y = 4 -> y=2