I could really use some help with this function. It's probly really easy but I don't know what I'm doing wrong.
If f(x)=xsquared+3x, find f(2-a).
I did it like this.
f(x)=xsquared+3x
f(2-a)=(2-a)squared+3(2-a)
f(2-a)=4-asquared+6-3a
f(2-a)=-asquared-3a+10
But my teacher told us that it was.
-asquared-7a+10
If you could help me I would really appreciate it. Thanks!