Answer: see below
Explanation:
coefficient: the numerical before a variable (3x)
constant: a number that is represented as an individual (5)
variable: any nonnumerical symbols (x)
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4x-7+15z-y+20
coefficient: 4 (4x), 15 (15z), -1 (-y)
constant: -7, 20
variable: x, y, z
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