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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?

2 Answers

1 vote

Answer:

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

Explanation:

I just got this right for the exam review on edge

User Ashir
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4 votes

Answer:

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.

User Kotucz
by
8.1k points
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