Which equation is part of solving the system by substitution? x plus y is equal to 11 4 x squared minus 3 y squared is equal to 8

From x + y = 11, solve for x to get x = 11 − y. Substitute 11 − y for x in 4x² − 3y² = 8, giving 4(11 − y)² − 3y² = 8. This is choice C.

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