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Set 10: Systems of Equations (Intermediate)

Explanation

Answer: A

Solve: {x=3y+12x+5y=13\begin{cases} x = 3y + 1 \\ 2x + 5y = 13 \end{cases}

A.

(7,2)(7, 2)

✓ Correct
B.

(4,1)(4, 1)

C.

(10,3)(10, 3)

D.

(5,43)(5, \frac{4}{3})

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Since x=3y+1x = 3 y + 1 is already isolated, substitute directly. Step 1: Substitute into second equation: 2(3 y + 1) + 5 y = 13$6y + 2 + 5 y = 1311y = 11y = 1$$ - First: $$4= 3(1) + 1 = 4$$ ✓ - Second: 2(4) + 5(1) = 8 + 5 = 13ChoiceBisincorrectbecause✓ Choice B is incorrect because2(4) + 5(1) = 13 \neq 24.ChoiceCisincorrectbecause. Choice C is incorrect because 2(10) + 5(3) = 35 \neq 24$. Choice D is incorrect.

Key Steps:

The correct answer is (7,2)(7, 2)

Why others are wrong:
B: Choice B is incorrect and may result from a calculation error.
C: Choice C is incorrect and may result from a calculation error.
D: Choice D is incorrect and may result from a calculation error.

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