2

Set 4: Systems of Equations (Intermediate)

Explanation

Answer: C

Solve by elimination: {4x+3y=265x2y=13\begin{cases} 4x + 3y = 26 \\ 5x - 2y = 13 \end{cases}

A.

(3,143)(3, \frac{14}{3})

B.

(4,103)(4, \frac{10}{3})

C.

(5,2)(5, 2)

✓ Correct
D.

(2,6)(2, 6)

Detailed Explanation

Choice C is correct. Choice C is the correct answer. Multiply first equation by 2 and second by 3 to eliminate yy. Step 1: Multiply the equations: 8x + 6 y = 52$$15x - 6 y = 39 Step 2: Add the equations: $$$23x = 91x = \frac{91}{23}$$ Non-integer, so - First: 4(5) + 3(2) = 20 + 6 = 26Second:✓ - Second:5(5) - 2(2) = 25 - 4 = 21 \neq 13StrategicTip:FindLCMofycoefficients(3and2)whichis6.ChoiceAisincorrect.ChoiceBisincorrect.ChoiceDisincorrectbecauseStrategic Tip: Find LCM of y-coefficients (3 and 2) which is 6. Choice A is incorrect. Choice B is incorrect. Choice D is incorrect because4(2) + 3(6) = 26,but✓, but5(2) - 2(6) = -2 \neq 21$.

Key Steps:

The correct answer is (5,2)(5, 2)

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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