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Set 3: Systems of Equations (Advanced)

Explanation

Answer: B

Which statement is true about this system? {2x+y=44x+2y=7\begin{cases} 2x + y = 4 \\ 4x + 2y = 7 \end{cases}

A.

The system has exactly one solution

B.

The system has no solution

✓ Correct
C.

The system has infinitely many solutions

D.

The lines are perpendicular

Detailed Explanation

Choice B is correct. Choice B is the correct answer. Step 1: Multiply the first equation by 2: 2(2 x + y) = 2(4)$4x + 2 y = 8$$$ Step 2: Compare with the second equation: - Our result: 4x + 2 y = 8Givensecondequation:- Given second equation:4x + 2 y = 7Theleftsidesareidentical( The left sides are identical (4x + 2 y),buttherightsidesaredifferent(), but the right sides are different (8\neq 7$$). Conclusion: The lines are parallel but don't overlap → no solution Strategic Tip: An impossible equation like "8 = 7" signals parallel lines with no intersection. Choice A is incorrect because one solution requires different slopes. Choice C is incorrect because infinitely many solutions requires both sides to match completely. Choice D is incorrect because perpendicular lines have slopes whose product is 1-1. Here both lines have slope 2-2, not perpendicular.

Key Steps:

The correct answer is The system has no solution

Why others are wrong:
A: Choice A 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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