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28 votes
If f(x) ==x²-1, and
g(x) = x + 5, then
f(g(x)) = [? ]x²+[ ]x + [ ]

If f(x) ==x²-1, and g(x) = x + 5, then f(g(x)) = [? ]x²+[ ]x + [ ]-example-1
User Aularon
by
3.5k points

1 Answer

7 votes
7 votes

Answer:

-1, -10, -26

Explanation:

f(x) = -x² - 1

g(x) = x + 5

f(g(x)) =

-(g(x))² - 1 = ==> plugin g(x) for x in f(x) in order to get f(g(x))

-(x + 5)² - 1 = ==> plugin x+5 for g(x)

-(x + 5)(x + 5) - 1 =

-(x(x + 5) + 5(x + 5)) - 1 = ==> distribute (x+5) to x and 5

-((x*x + 5*x) + (5*x + 5*5)) - 1 = ==> simplify

-(x^2 + 5x + 5x + 25) - 1 =

-(x^2 + 10x + 25) - 1 =

-x^2 - 10x - 25 - 1 = ==> distribute the negative sign to x^2, 10x, and 25

-x^2 - 10x - 26 = -1x^2 + (-10x) + (-26)

Subtracting by a positive number is equivalent to adding by a negative number

Answer: -1, -10, -26

User Kasinath Kottukkal
by
2.7k points
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