To check which pair is a solution of the equation \(1.5x - 2y = 8\), we need to substitute the given points into the equation and see if the left-hand side equals the right-hand side (8).
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Peter believes (-4, 7) is a solution: \[ 1.5(-4) - 2(7) = -6 - 14 = -20 \quad (\text{not 8}) \]
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Fiona believes (4, 7) is a solution: \[ 1.5(4) - 2(7) = 6 - 14 = -8 \quad (\text{not 8}) \]
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Mary believes (4, -7) is a solution: \[ 1.5(4) - 2(-7) = 6 + 14 = 20 \quad (\text{not 8}) \]
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Sam believes (-4, -7) is a solution: \[ 1.5(-4) - 2(-7) = -6 + 14 = 8 \quad (\text{is 8}) \]
The correct solution is Sam's belief that \((-4, -7)\) is a solution to the equation \(1.5x - 2y = 8\).