Solve the system by substitution. ( explain how you did it ill give brainliest)

-x-y-z=-8
-4x+4y+5z=7
2x+2z=4

  (x, y, z) = (3, 6, -1

Step-by-step explanation:

You can make a simple expression to substitute for x using the last equation.

  2x = 4 -2z

  x = 2 - z . . . . . . divide by 2

Now, substitute that into the first equation:

  -(2 -z) -y -z = -8 . . . .substitute for x

  -2 +z -y -z = -8 . . . . eliminate parentheses

 -2 -y = -8 . . . . . . . . . simplify

  6 = y . . . . . . . . . . . . add 8+y

We can substitute for both x and y in the second equation:

  -4(2 -z) +4(6) +5z = 7

  -8 +4z +24 +5z = 7 . . . . . eliminate parentheses

  9z = -9 . . . . . . . . . . . . . . .simplify, subtract 16

  z = -1 . . . . . . . . . . . . . . . . . divide by 9

And from our expression for x, we get ...

  x = 2 - z = 2 -(-1) . . . . . substitute for z

  x = 3

The solution is (x, y, z) = (3, 6, -1).

d. bc = 12 and ef = 16

step-by-step explanation:

we are given that δabc : δdef such that .

also, it is given that

so, from the options, we need that .

a.

b.

c.  

d.

as, we can see that only option d gives the same ratio as i.e. .

hence, the possible lengths are bc = 12 and ef = 16.