6

Set 2: Systems of Equations

Explanation

Answer: C

Solve: {6x2y=143x+y=13\begin{cases} 6x - 2y = 14 \\ 3x + y = 13 \end{cases}

A.

(103,3)(\frac{10}{3}, 3)

B.

(2,1)(2, -1)

C.

(3,4)(3, 4)

✓ Correct
D.

(4,1)(4, 1)

Detailed Explanation

Choice C is correct. Choice C is the correct answer. Step 1: Multiply the second equation by 2: 6x+2y=266x + 2 y = 26 Step 2: Add to the first equation: (6 x - 2 y) + (6 x + 2 y) = 14 + 26$12x = 40$x = \frac{10}{3} Non-integer. - First: 6(3)2(4)=188=10146(3) - 2(4) = 18 - 8 = 10 \neq 14 - Second: 3(3)+4=133(3) + 4 = 136(3)2(4)=106(3) - 2(4) = 10, so 6x2y=106x - 2 y = 10. Step 1: Multiply second by 2: 6x+2y=266x + 2 y = 26 Step 2: Add to first: $$$12x = 36x = 3$$ Step 3: Substitute: $$3(3) + y = 13y = 4$$ Solution: (3, 4)Verification:Verification:6(3) - 2(4) = 10and✓ and3(3) + 4 = 13StrategicTip:Multiplyingtomatchcoefficientsisoftenfasterthanisolatingvariables.ChoiceAisincorrectthiswastheintermediatecalculationerror.ChoiceBisincorrectbecause✓ Strategic Tip: Multiplying to match coefficients is often faster than isolating variables. Choice A is incorrect—this was the intermediate calculation error. Choice B is incorrect because6(2) - 2(-1) = 14,but✓, but3(2) + (-1) = 5 \neq 13.ChoiceDisincorrectbecause. Choice D is incorrect because 6(4) - 2(1) = 22 \neq 10$.

Key Steps:

The correct answer is (3,4)(3, 4)

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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