Question 207174
(1),,,   m^3 * n^3= (mn)^3
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m^3 =m*m*m,,,,,,n^3=n*n*n,,,,,
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m^3*n^3 = m*n*m*n*m*n = (mn)^3
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(2),,,2*sqrt(x)+3*sqrt(x) =5*sqrt(x)
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(3),,,x^2-x^3,,,that's  as  simple  as  it  can  be
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(4),,,,(x+y)^5 / (x+y)^4 = (x+y)^{5-4} = (x+y)^1= x+y
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ex,,  x^5 / x^4 =(x*x*x*x*x)/(x*x*x*x*)= x
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that  is,  to  divide like  terms  with  exponents, subtract  exponents.
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Likewise,  to  multiple like  terms with  exponents,  add  exponents.