7

Set 17: Systems of Equations (Intermediate)

Explanation

Answer: C

Is the point (1,8)(1, 8) a solution to the system? {2x+y=105xy=3\begin{cases} 2x + y = 10 \\ 5x - y = -3 \end{cases}

A.

No

B.

Only for the first equation

C.

Yes

✓ Correct
D.

Cannot be determined

Detailed Explanation

Choice C is correct. Choice C is the correct answer. To verify if (1,8)(1, 8) is a solution, we substitute x=1x = 1 and y=8y = 8 into both equations. First equation: 2x+y=102(1)+8=2+8=102x + y = 102(1) + 8 = 2 + 8 = 10 ✓ (True) Second equation: 5xy=35(1)8=58=35x - y = -35(1) - 8 = 5 - 8 = -3 ✓ (True) Since the point satisfies both equations, it is a solution to the system. Strategic Tip: A point must satisfy ALL equations in a system to be considered a solution. Choice A is incorrect because the point does satisfy both equations. Choice B is incorrect because the point satisfies both equations, not just the first. Choice D is incorrect because we can always determine if a point is a solution through direct substitution.

Key Steps:

The correct answer is Yes

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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