Math, asked by blackspearrow9739, 1 year ago

If f(x)=x2−1,g(x)=2x+5, then find (fog)(x).

Answers

Answered by preetkaur9066
0

Answer:

Another way of looking at it:

set

g

(

x

)

y

1

=

x

+

2

...

...

...

.

.

E

q

u

a

t

i

o

n

(

1

)

set

f

(

x

)

y

2

=

2

x

5

...

...

.

.

E

q

u

a

t

i

o

n

(

2

)

(

f

o

g

)

(

x

)

is such that as f is before the g in

(

f

o

g

)

(

x

)

so wherever in

f

(

x

)

you see

x

you substitute

y

1

That is; you are substituting

E

q

u

a

t

i

o

n

(

1

)

into any

x

that is in

E

q

u

a

t

i

o

n

(

2

)

So:

(

f

o

g

)

(

x

)

=

2

(

y

1

)

5

but

y

1

=

x

+

2

So:

(

f

o

g

)

(

x

)

=

2

(

x

+

2

)

5

(

f

o

g

)

(

x

)

=

2

x

+

4

5

=

2

x

1

Hope it helps you

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