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# Maths question (C1) {function notation} watch

1. f(x) = 7x^3 + 11x^2 - 9x - 7 + g(x) = x^3 - 6x^2 + 4x - 7

i get 8x^3+5x^2-5x-14 but the website is saying its wrong?...anyone know the right answer?

also im complety stuck on on this question

the function f(x) i defined by :x^2+ax+b<---------so its quadratic

a and b are constants<---------what does this mean?

it is known that : f(0)=7 and f(-2)=17

find values of A and B

then the next part of question says : use values of A and B to solve this question f(x)=35

would appreciate anyone to offer any help on this question , cheers

p.s i would show you the website but its one the school has to pay for so im not certain ill be allowed to give away the password/username
2. Anyone....

A constant is a fixed number. You need to use the information f(0) = 7 and f(-2)=17 to find out what numbers a and b are.

For example,
, so
4. (Original post by cosmicalgebra)
f(x) = 7x^3 + 11x^2 - 9x - 7 + g(x) = x^3 - 6x^2 + 4x - 7

i get 8x^3+5x^2-5x-14 but the website is saying its wrong?...anyone know the right answer?

also im complety stuck on on this question

the function f(x) i defined by :x^2+ax+b<---------so its quadratic

a and b are constants<---------what does this mean?

it is known that : f(0)=7 and f(-2)=17

find values of A and B

then the next part of question says : use values of A and B to solve this question f(x)=35

would appreciate anyone to offer any help on this question , cheers

p.s i would show you the website but its one the school has to pay for so im not certain ill be allowed to give away the password/username
Compare the left hand side to the right hand side and check what you have to do to the LHS to get to the RHS, this should give you G(x), i.e : 7x^3 turns to x^3 so g(x) must start with -6x^3.

for your second part, f(0) basically means replacing x as 0 so x^2+ax+b, = (0)^2 + 0x + b = 7. therefore b = 7? take it from there?
5. (Original post by Extricated)
Compare the left hand side to the right hand side and check what you have to do to the LHS to get to the RHS, this should give you G(x), i.e : 7x^3 turns to x^3 so g(x) must start with -6x^3.

for your second part, f(0) basically means replacing x as 0 so x^2+ax+b, = (0)^2 + 0x + b = 7. therefore b = 7? take it from there?
ok thanks, ill give it ago from here
6. (Original post by Dragon)

A constant is a fixed number. You need to use the information f(0) = 7 and f(-2)=17 to find out what numbers a and b are.

For example,
, so
thanks, ill see what i get
7. (Original post by Extricated)
Compare the left hand side to the right hand side and check what you have to do to the LHS to get to the RHS, this should give you G(x), i.e : 7x^3 turns to x^3 so g(x) must start with -6x^3.

for your second part, f(0) basically means replacing x as 0 so x^2+ax+b, = (0)^2 + 0x + b = 7. therefore b = 7? take it from there?
ok, ive got A=-3 and B=7

thanks for help
8. ok cheers, i can do it now...done all question and got it them right!

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