I:2x – y + z = 7
II:x + 2y – 5z = -1
III:x – y = 6

you can first use III and substitute x or y to eliminate it in I and II (in this case x):
III: x=6+y
-> substitute x in I and II:
I': 2*(6+y)-y+z=7
12+2y-y+z=7
y+z=-5

II':(6+y)+2y-5z=-1
3y+6-5z=-1
3y-5z=-7

then you can subtract II' from 3*I' to eliminate y:
3*I'=3y+3z=-15

3*I'-II':
3y+3z-(3y-5z)=-15-(-7)
8z=-8
z=-1

insert z in II' to calculate y:
3y-5z=-7
3y+5=-7
3y=-12
y=-4

insert y into III to calculate x:
x-(-4)=6
x+4=6
x=2

so the solution is
x=2
y=-4
z=-1

3 0

3 years ago

How are proptions and percents the same

Lelechka [254]

Answer:

1 would be 10%, but a proportion is a ratio, as in this case 10/100 = 1/10= . 1, but 10% is not a ratio in of itself, but is a proportion of 100. % means OF one hundred. A proportion is a number TO another number.

Step-by-step explanation:

4 0

2 years ago