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3 years ago

For the functions f(x) = x^2+ 8x + 2 and g(x) = -5+9, find (f•g)(x)and (f.g)(-1).

Mathematics

1 answer:

Ne4ueva [31]3 years ago

6 0

Answer: (f·g)(x) = -5x³ - 31x² + 62x + 18

(f·g)(-1) = -70

(fog)(x) = 25x² - 130x + 155

(fog)(-1) = 310

Step-by-step explanation:

f(x) = x² + 8x + 2 g(x) = -5x + 9

(f·g)(x) = (x² + 8x + 2)(-5x + 9)

= -5x³ + 9x²

- 40x² + 72x

- 10x + 18

= -5x³ - 31x² + 62x + 18

(f·g)(-1)= -5(-1)³ - 31(-1)² + 62(-1) + 18

= -5(-1) - 31(1) - 62 + 18

= 5 - 31 - 62 + 18

= -70

****************************************************************************************

(fog)(x) = (-5x + 9)² + 8(-5x + 9) + 2

= 25x² - 90x + 81

- 40x + 72

+ 2

= 25x² - 130x + 155

(fog)(-1) = 25(-1)² - 130(-1) + 155

= 25 + 130 + 155

= 310

It wasn't clear if you wanted multiplication or composition so I solved both.

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Answer:

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Step-by-step explanation:

Given:

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Let $t_1$ be the time taken to drive to lake.

Let $t_2$ be the time taken to drive back from lake.

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Solution:

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Formula for time is given as:

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$t_1 = \dfrac{D}{60}\ hrs$

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Putting in equation (1):

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