Question

Resolva o sistema pelo método de Cramer

A) 3x -2y=0 c) x+y=7
x+y=5 2x-y=2

B) x+y=2
3x+2y=3

Answer 1

a) x+y = 5 (2)
3x-2y = 0

x+y = 5
5x = 10

5x = 10
x = 10/5
x = 2

x+y = 5
2+y = 5
y = 5-2
y = 3

b) x+y = 2 (-2)
3x+2y = 3

x+y = 2
x = -1

x+y = 2
-1+y = 2
y = 2+1
y = 3

c) x+y = 7 (1)
2x-y = 2

x+y=7
3x = 9

3x = 9
x = 9/3
x = 3

x+y = 7
3+y = 7
y = 7-3
y = 4