4

Set 9: Systems of Equations (Intermediate)

Explanation

Answer: C

For what value of pp does the system have no solution? {3x+6y=9x+2y=p\begin{cases} 3x + 6y = 9 \\ x + 2y = p \end{cases}

A.

p=9p = 9

B.

p=6p = 6

C.

Any value except 3

✓ Correct
D.

p=3p = 3

Detailed Explanation

Choice C is correct. Choice C is the correct answer. Step 1: Divide the first equation by 3: 3x+6y3=93x+2y=3\frac{3 x + 6 y}{3} = \frac{9}{3}x + 2 y = 3 Step 2: For the system to have: - Infinitely many solutions (same line): p=3p = 3 - No solution (parallel): p3p \neq 3 Strategic Tip: When left sides are identical after simplification, different right sides = no solution. Choice A is incorrect because while p=9p = 9 gives no solution, it's not the only value. Choice B is incorrect because while p=6p = 6 gives no solution, it's not the only value. Choice D is incorrect because p=3p = 3 gives infinitely many solutions, not no solution.

Key Steps:

The correct answer is Any value except 3

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