Answer:
84x^10
Step-by-step explanation:
The coefficients multiply, and the exponents add.
(4x)( -3x^6)(-7x^3) = (4)(-3)(-7)x^(1+6+3) = 84x^10
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The rule for exponents is ...
(x^a)(x^b) = x^(a+b)
The answer is C, 84x^12.
