Algebra practice question

Answer: A. 3x − 4y = 8

Clear the fraction by multiplying every term by 4: 4y = 3x − 8. Rearrange: 3x − 4y = 8. Check with x = 4: the original gives y = 1, and 3(4) − 4(1) = 8.

Why the other answers are wrong

B. 3x + 4y = 8

The sign of the y term is wrong. Moving 4y to the other side of 3x − 8 = 4y gives 3x − 4y, not 3x + 4y.

C. 4x − 3y = 8

The coefficients are swapped. Multiplying by 4 gives 4y = 3x − 8, so x has the 3 and y has the 4.

D. 3x − 4y = −2

The constant −2 was carried over without being multiplied by 4. Every term, including −2, is multiplied: −2 × 4 = −8, which becomes +8 on the other side.

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