What is the solution to the system of equations? -3x-4y+z=-1 2x+y-z=-8 x+8y-z=23 a. (-3,4,6) b. (4,-3,-1) c. (-3,4,8) d. (3,-4,-6)

The answer is A (-3,4,6).

Step-by-step explanation:

1 Solve for z in -3x-4y+z=-1

z=3x-1+4y

2 Substitute z=3x-1+4y into 2x+y-z=-8

-x-3y+1=-8

3 Substitute z=3x-1+4y into x+8y-z=23

-2x+4y+1=23

4 Solve for x in -x-3y+1=-8

x=-3y+9

5 Substitute x=-3y+9 into z=3x-1+4y

z=-5y+26

6 Substitute x=-3y+9 into -2x+4y+1=23

10y-17=23

7 Solve for y in 10y-17=23

y=4

8 Substitute y=4 into z=-5y+26

z=6

9 Substitute y=4 into x=-3y+9

x=-3

10 Therefore,

x=-3

y=4

z=6

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb

step-by-step explanation: