Question

PLEASE HELP WITH THIS ‼️

Answer 1

A. x = 12, y = 11, z = 2

Explanation:

`x + y + z = 25`

`5x + y + 9z = 89`

`- 7x + 6y + 6z = - 6`

• Solve explicitly for 2 variables then substitute them into the third equation. Solving for x and z is a bit easier in this case.

`x = 25 - y - z`

• Substitute this in 5x + y + 9a = 89 then solve for z

`5(25 - y - z) + y + 9z = 89`

`- 5y + y - 5z + 9z = 89 - 125`

`4z - 4y = - 36`

`(4z - 4y)/(4) = ( - 36)/(4)`

`z = y - 9`

• Substitute both x and z into the third equation

`- 7(25 - y - (y - 9)) + 6y + 6(y - 9) = - 6`

`- 175 + 7y + 7y - 63 + 6y + 6y - 54 = - 6`

`26y - 292 = - 6`

`26y = 286`

`y = 11`

• Find z then find x by substituting the values you found.

`z = 11 - 9 = 2`

`x = 25 - 11 - 2 = 12`

Values for x, y and z are:

`x = 12`

`y = 11`

`z = 2`