SOLUTION: For all parts of this question use the function f(x)=2x^2-x+1 a) Evaluate the following and simplify the expression (i) f(a+1) (ii) f(3b)

Algebra ->  Functions -> SOLUTION: For all parts of this question use the function f(x)=2x^2-x+1 a) Evaluate the following and simplify the expression (i) f(a+1) (ii) f(3b)       Log On


   

Question 318104: For all parts of this question use the function f(x)=2x^2-x+1
a) Evaluate the following and simplify the expression

(i) f(a+1) (ii) f(3b)

This is what I have so far, I am not sure where to go from here:
f(a+1)=2(a+1)^2-(a+1)+1
= 2a^2+2^2-a-1+1

Any guidance would be appreciated...
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
i)

f%28x%29=2x%5E2-x%2B1 Start with the given function.


f%28a%2B1%29=2%28a%2B1%29%5E2-%28a%2B1%29%2B1 Plug in x=a%2B1


f%28a%2B1%29=2%28a%5E2%2B2a%2B1%29-%28a%2B1%29%2B1 FOIL.


f%28a%2B1%29=2a%5E2%2B4a%2B2-a-1%2B1 Distribute.


f%28a%2B1%29=2a%5E2%2B3a%2B2 Combine like terms.

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ii)

f%28x%29=2x%5E2-x%2B1 Start with the given function.


f%283b%29=2%283b%29%5E2-3b%2B1 Plug in x=3b


f%283b%29=2%289b%5E2%29-3b%2B1 Square 3b to get 9b%5E2.


f%283b%29=18b%5E2-3b%2B1 Multiply 2 and 9b%5E2 to get 18b%5E2