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Algebra homework help pls

Algebra homework help pls-example-1
User Micmoo
by
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1 Answer

5 votes

Answer:

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

Explanation:


\begin{cases}x+y+z=25&\left( 1\right) \\ 5x+y+9z=89&\left( 2\right) \\ -7x +6y+6z=-6&(3)\end{cases}

(3) - 6×(1) ⇒ -7x - 6x = -6 - 6×25 = -156

⇒ -13x = -156

x = 12

(2) - (1) ⇒ 4x + 8z = 89 - 25 = 64

⇒ 4x + 8z = 64

⇒ 8z = 64 - 4x

Since x = 12 ⇒ 8z = 64 - 48 = 16

z = 16/2 = 8

User Sliver
by
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