Question

considere o sistema linear

x-y+z+t=6
2y-z+2t=9
3z-t=5
2t=8

o valor de x+y+z+t é igual a:

a)1
b)3
c)4
d)8
e)10

Answer 1

2t= 8
t= 8/2
t=4

3z-t=5
3z= 5+ 4
3z=9
z=9/3
z=3

2y-z+ 2t=9
2y- 3 + 2. 4 = 9
2y= 9-5
2y= 4
y= 4/2
y= 2

x-y+z+t=6
x- 2 + 3 + 4= 6
x=6-5
x= 1

x+y+z+t=
1+2+3+4=10