Math(Relations and Functions)急!!!15點

1. If two functions are definded as: f(x)=3x-1 and g(x)=x^2+1,
Calculate:
f(3)+g(-3)

2. If f(x)=-x^2-3x+2, evalute the values of:
a. f(4)
b. f(-2m)

3. If f(x)=2x^2-3x+5, evaluate the expression when f(2x+1)

4. Determine the expression for: f(2x)-2g(x) if we use the functions
f(x)=2(x+5)+3 and g(x)=3(x-1)-3

5. The amount of grabage collected in a city varies directly as the
population. If a city of 30000 people generates 132 tonnes of grabage,
how many tonnes of grabage would you expect from a city of
67000 people?

6. An object is supported from the end of a spring as shown in the
diagram to the right.
The distace the spring stretches varies partially to the mass of the
object.
When a 2kg mass is supported, the spring stretches 6cm.
When a 6kg mass is supported, the spring stretches 12cm.
a. What is the partial variation equation for the above situation.
b. Use the partial variation equation to determine how many cm a
4kg mass should stretch the spring.

7. The cost of renting a car for a day varies partially with the distance
driven. It costs $54 to drive 400km and it costs $72 to drive 600km.
a. What is the fixed cost?
b. What is the cost per km?
c. What is the partial varation equation?
(Let C=cost and k=km driven. Write your equation in form
C=(cost per km)k+fixed cost)
d. How far could a person drive for $90?


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Thanks a lot.