Question

Dimitri determined that he ordered pair (2,-2) is a solution to the system of linear equations 7x +9y=-4 and 5x -2y=6 as shown What was dimitri's mistake?

Answer 1

D.)He made a mistake in his calculations when substituting the ordered pair into the equation 5x – 2y = 6 and simplifying.

Explanation:

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Answer 2

Therefore
`((46)/(59),-(62)/(59) )` is a solution of given liner equations.

Explanation:

Given system of equation are

7x+9y=-4..............(1)

5x-2y=6...............(2)

Equation (1)×5 - equation (2)×7

35x +45y-(35x-14y)= -20-42

⇔ 35x+45y-35x+14y = -62

⇔59 y = -62

`\Leftrightarrow y =-(62)/(59)`

Putting the value of y in equation (1)

`7x +9.(-(62)/(59) )= -4`

`\Leftrightarrow 7x += -4+(558)/(59)`

`\Leftrightarrow 7x = (322)/(59)`

`\Leftrightarrow x =(322)/(59* 7)`

`\Leftrightarrow x =(46)/(59)`

Therefore
`x =(46)/(59)` and
`y =-(62)/(59)`

Therefore
`((46)/(59),-(62)/(59) )` is a solution of given liner equations.