Solve the system by substitution.
-x-y-z = -8
- 4x + 4y + 5z = 7
2x + 2z = 4

show all steps.

Using the substitution method, the solution to the system of equations given is: (3, 6, -1).

Given the system:

-x-y-z = -8 --> eqn. 1

- 4x + 4y + 5z = 7 --> eqn. 2

2x + 2z = 4 --> eqn. 3

Rewrite eqn. 3 to make x the subject of the formula.

Thus:

Substitute x = 2 - z into eqn. 1 to find y.

Substitute x = 2 - z and y = 6 into eqn. 2 to find z

Substitute z = -1 into eqn. 3 to find x.

Therefore, using the substitution method, the solution to the system of equations given is: (3, 6, -1).

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The solution set of given equations -x-y-z = -8 and - 4x + 4y + 5z = 7 and 2x + 2z = 4  is (3, 6, -1)

Solution:

Given, set linear equations are

-x – y – z = -8 ⇒ x + y + z = 8 → (1)

-4x + 4y + 5z = 7 ⇒ 4x – 4y – 5z = -7 → (2)

2x + 2z = 4 ⇒ x + z = 2 → (3)

We have to solve the above given equations using substitution method.

Now take (3), x + z = 2 ⇒ x = 2 – z  

So substitute x value in (1)  

(1) ⇒ (2 – z) + y + z = 8 ⇒ 2 + y + z – z = 8 ⇒ y + 0 = 8 – 2 ⇒ y = 6.

Now substitute x and y values in (2)

(2) ⇒ 4(2 – z) – 4(6) – 5z = - 7 ⇒ 8 – 4z – 24 – 5z = -7 ⇒ -9z – 16 = -7 ⇒ 9z = 7 – 16 ⇒ 9z = -9 ⇒ z = -1

Now substitute z value in (3)

(3) ⇒ x – 1 = 2 ⇒ x = 2 + 1 ⇒ x = 3

Hence, the solution set of given equations is (3, 6, -1).

answer:

total cost for tiles and paints is $924.  

step-by-step explanation:

we have been given that a community hall is in the shape of a cuboid. the hall is 40m long 15m high and 3m wide.

the paint will be required for 4 walls and ceiling.

let us find area of walls and ceiling.

therefore, the area of walls and ceiling is 1410 square meters.

given: cost for 10 litre of paint is $10 and 10 litre paint covers 25 square meter. therefore,

therefore, the total painting cost is $564.

tiles will be required for floor. let us find the area of floor.

given: 1m squared floor tiles costs $3. so,

therefore, the total tiles cost is $360.

now let us find combined total cost of tiles and paint.

therefore, the combined total cost of tiles and paint is $924.