Answers in bold:
expression one: 6 + x + 9 = x + 15
Expression two: x + 2 + 8x = 9x + 2
Expression three: 4x + 3y + 23y = 4x + 26y
expression four: 4 (15a) = 60a
expresion five: x²+2x+3x²+10x = 4x² + 12x = 4x(x + 3)
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