8

Set 4: Systems of Equations (Intermediate)

Explanation

Answer: B

Solve using substitution: {x+4y=223x2y=10\begin{cases} x + 4y = 22 \\ 3x - 2y = 10 \end{cases}

A.

(8,3.5)(8, 3.5)

B.

(6,4)(6, 4)

✓ Correct
C.

(5,4.25)(5, 4.25)

D.

(7,3.75)(7, 3.75)

Detailed Explanation

Choice B is correct. Choice B is the correct answer. Isolate xx from the first equation. Step 1: From x+4y=22x + 4 y = 22: x=224yx = 22 - 4 y Step 2: Substitute into the second equation: 3(22 - 4 y) - 2 y = 10$66- 12 y - 2 y = 1066- 14 y = 10-14 y = -56y = 4$$ Step 3: Find x: $$x = 22 - 4(4) = 22 - 16 = 6$$ Solution: (6, 4)Verification:Verification:3(6) - 2(4) = 18 - 8 = 10StrategicTip:Isolating✓ Strategic Tip: Isolatingxwaseasierheresinceitscoefficientis1inthefirstequation.ChoiceAisincorrectbecausewas easier here since its coefficient is 1 in the first equation. Choice A is incorrect because3(8) - 2(3.5) = 24 - 7 = 17 \neq 10.ChoiceCisincorrectbecause. Choice C is incorrect because 3(5) - 2(4.25) = 15 - 8.5 = 6.5 \neq 10.ChoiceDisincorrectbecause. Choice D is incorrect because 3(7) - 2(3.75) = 21 - 7.5 = 13.5 \neq 10$.

Key Steps:

The correct answer is (6,4)(6, 4)

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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