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Answer:
Question 10:
Answer: b.
[tex]{ \tt{f(x) = 5 {x}^{2} + 9x - 4}} \\ { \tt{g(x) = - {8x}^{2} - 3x - 4 }}[/tex]
(f + g)x, add f(x) and g(x):
[tex]{ \tt{(f + g)x = (5 - 8) {x}^{2} + (9 - 3)x - 4 - 4}} \\ { \tt{(f + g)x = - 3 {x}^{2} + 6x - 8}}[/tex]
Question 11:
Answer: a.
In relation with solution of question 10, same procedure:
[tex]{ \tt{(f - g)x = - 3 {x}^{3} + (1 - 2) {x}^{2} + ( - 3 - 4)x + 9 - ( - 9)}} \\ { \tt{(f - g)x = - 3 {x}^{3} - {x}^{2} - 7x + 18 }}[/tex]