given f(x)=x^2+2x, find f(a-3)?

Question

a. a^2-4a+3
b. a^2+2a-15
c. a^2+8a+3
d. a^2-4a+6

Answer 1

(a - 3)² + 2.(a - 3)
a² - 6a + 9 + 2a - 6
a² - 4a + 3
ANSWER a.

Answer 2

Basically you plug (a-3) in for x in the first function.

(a-3)^2 + 2(a-3)
a^2-6a+9+2a-6
a^2-4a+3

The answer is A.

Answer 3

f(x)=x^2+2x, find f(a-3)

Forgive me. But does the word "substitution" ring a bell?
f(x)=x^2+2x
f(a-3) =(a-3)^2 + 2(a-3)

You figure out (a-3)^2 by application of the distributive property-- a(b+c)=ab+ac, then the commutative property for multiplication ab=ba, and then the distributive property again.

You figure out 2(a-3) by applying the distributive property again.

When you get them figured out, add them together. It main mean application of the associative property for addition (a+b)+c = a+(b+c), and the commutative property for addition a+b=b+a, and probably that distributive property again.

You can probably get somebody to do this for you, but you really need practice in applying these properties..

Answer 4

replace x with a - 3 so u would have f(a-3) = (a-3)^2+2(a-3)
and solve use the foil method first outer inner last

Answer 5

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