Question

If f(x) = -7x+2 and g(x) = square root of x+3,
what is (fºg)(-2)?

Answer 1

Answer:

(fog)(-2)=-5

Step-by-step explanation:

Given

f(x)= -7x+2

and

g(x)= √(x+3)

For finding (fog)(-2), we have to find (fog)(x) first

In order to find (fog)(x) we will put the value of g(x) in f(x) in place of x.

(fog)(x)= -7g(x)+2

Putting the value of g(x)  

(fog)(x)= -7√(x+3)+2

We have to find (fog)(-2), so we have to put at the place of x in the composition

(fog)(-2)= -7√(-2+3)+2

(fog)(-2)= -7√1+2

= -7(1)+2

= -7+2

=-5

So,

(fog)(-2)=-5

Answer 2

For this case we have the following equations:$f (x) = - 7x + 2\\g (x) = \sqrt {x + 3}$

We must find $(f_ {o} g) (x):$

By definition of composition of functions we have to:

$(f_ {o} g) (x) = f (g (x))$

So:

$(f_ {o} g) (x) = - 7 \sqrt {x + 3} +2$

Now, we find f (g (-2)):

$(f_ {o} g) (- 2) = - 7 \sqrt {-2 + 3} + 2 = -7 \sqrt {1} + 2 = -7 + 2 = -5$

ANswer:

-5