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What is the solution to this system of equations? x + 2y = 9 3x - 2y = 3 A.(3, 3) B.(3,5) C. (4, 12) D. (9,7)​

User EggMeister
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1 Answer

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Answer:

A. (3, 3)

Explanation:

The coefficients of y are opposites, so adding the two equations will eliminate y.

(x +2y) +(3x -2y) = (9) +(3)

4x = 12 . . . simplify

x = 3 . . . . . divide by 4

Using the first equation, we can find y:

3 +2y = 9 . . . . . .substitute for x

2y = 6 . . . . . . . . subtract 3

y = 3 . . . . . . . . . . divide by 2

The solution is (x, y) = (3, 3).

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Additional comment

For this problem, it is easy to just try the answers. You don't have to go far to show the first answer (A) satisfies both equations.

3 + 2(3) = 9; 3(3) -2(3) = 3

User Tony Gil
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