Functions eg. f(x+2), f(2x)+2,  TOPIC_SOLVED

Quadratic equations and inequalities, variation equations, function notation, systems of equations, etc.

Functions eg. f(x+2), f(2x)+2,  TOPIC_SOLVED

Postby Nats on Mon Aug 19, 2013 11:33 am

If f(x) = 4x^2 + 3x - 2 write down the following in their simplest form.

a) f(x) +4 = 4x^2 + 3x - 2 +4
= 4x^2 +3x + 2 (this one I think i understand.)

b) f(2x) + 2 = i dont know how to do this one.
= 2( 4x^2 + 3x - 2) +2?

c) f(x+2) - 20 = ?

d) f (x-1)+1 + ?

e) f(x/2) = 4x^2 + 3x - 2/2 ??

f) f (3x+2) =?

If you explained b) i'd be able to figured out f) i hope, and if you explained just one from c) or d)

Thank you so much.

Regards,
Nats
Nats
 
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Re: Functions eg. f(x+2), f(2x)+2,

Postby jg.allinsymbols on Mon Aug 19, 2013 8:53 pm

If f(x) = 4x^2 + 3x - 2

AND
b) f(2x) + 2 = i dont know how to do this one.
= 2( 4x^2 + 3x - 2) +2?


Just substitute for x. You have a defined function, f(x) and you have an expression which uses f(x), but the input shown to use in the function is 2x. SUBSTITUTE 2x for x and then simplify the entire expression in question #b. In other words, REPLACE x WITH 2x in f(x).

A large help on starting, is this:
The function is like this, showing where the input goes: 4(___)^2+3(___)-2
What must you put inside the grouping symbols?
Question #b wants 4(__)^2+3(__)-2+2
and the input for the function f(x) which question #b wants is 2x.
jg.allinsymbols
 
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Re: Functions eg. f(x+2), f(2x)+2,

Postby Nats on Tue Aug 20, 2013 8:30 am

b) 4(4x^2)+3(2x)+2-2
= 16x^2+6x

I'm so grateful for your help. I didn't think I'd get a reply so soon considering none of the problems on the first page were answered. Then you not only helped me but you went and answered like the whole page of other learners problems as well.

Thank you so much, you're just awesome!
Have a blessed day.
Nats
 
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Joined: Mon Aug 19, 2013 11:14 am


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