# If #f(x)=x^2 + 2x +3#, then how do you find f(a-1)?

##### 2 Answers

May 28, 2016

#### Answer:

#### Explanation:

Substitute x = a-1 into function.

#rArrf(a-1)=(a-1)^2+2(a-1)+3# expand brackets and collect like terms.

#rArr(a-1)^2+2(a-1)+3=a^2-2a+1+2a-2+3#

#=a^2+2#

May 28, 2016

#### Answer:

It is enough to substitute

#### Explanation:

It is enough to write

then it is just a matter of doing a bit of algebra