Respuesta :
Part A:( 3 x² - 2 x - 1 ) + ( 9 x + 2 x² - 3 ) = = 3 x² + 2 x² - 2 x + 9 x - 1 - 3 = = 5 x² + 7 x - 4Part B :( 5 x³+ 4 x² + x + 3 ) - ( 5 x² + 7 x - 4 ) = = 5 x³ + 4 x² - 5 x² + x - 7 x + 3 + 4 = = 5 x³ - x² - 6 x + 7Part C:Answers in Part A and in Part B shows that the polynomials are closed under addition and subtraction.Closure under addition: while adding polynomials the variables and their exponents do not change. Only their coefficients will possibly change.Closure under subtraction: while subtracting polynomials the variables and their exponents do not change, only their coefficients will possibly change.
Answer:
Part A:
( 3 x² - 2 x - 1 ) + ( 9 x + 2 x² - 3 ) =
= 3 x² + 2 x² - 2 x + 9 x - 1 - 3
= 5 x² + 7 x - 4
Part B :
( 5 x³+ 4 x² + x + 3 ) - ( 5 x² + 7 x - 4 ) =
= 5 x³ + 4 x² - 5 x² + x - 7 x + 3 + 4 =
= 5 x³ - x² - 6 x + 7
Part C: Polynomials are always closed if under addition or subtraction. Both parts A and B are polynomials.