A variable is a letter that replaces an unknown number.
280 is the answer
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Answer:
5
Step-by-step explanation:
3+9x=11x-7
subtract 9x from both sides
3=2x-7
add 7 to both sides
10=2x
divide by 2 on both sides
5=x
Answer:
Step-by-step explanation:
3x(x^2+4)
=3x^2+12x