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
Answer:
9 7/8 - ( -2 4/5 - 1/2) = 13.175
Step-by-step explanation:
Hope this is correct and helps.
.................................:........:.................
Answer:
Samuel can type 40 words per minute
Step-by-step explanation:.
Then how many hours will it take for him to type 2.6 words times 10 to the power of five words
=> 2.6 words time 10 to the power of 5
=> 2.6 x 10^5
=> 2.6 x 100 000
=> 260 000 words in all.
Now, we need to find the number of words Samuel can type in a hour
=> 40 words / minutes , in 1 hour there are 60 minutes
=> 40 x 60
=> 2 400 words /hour
Now, let’s divide the total of words he need to type to the number of words he can type in an hour
=> 260 000 / 2 400
=> 108.33 hours.
