14.) f(x)= -x^2- 3x;g(x)=6x^2 (15.) f(x)=x-2;g(x)=4-3x^2 16.) f(x)=3x^2-x;g(x)=3x-9?

Question

find f=g and f-g? i dont under stand

Answer 1

14)
f=g
-x^2-3x=6x^2
Subtract 6x^2 from both sides:
-7x^2-3x=0
Factor out a -x:
-x(7x+3)=0
-x=0
7x+3=0
x=0 and -3/7

f-g
f(x)-g(x)
-x^2-3x-(6x^2)
-x^2-3x-6x^2
-7x^2-3x

Just apply this example to the other two problems

Answer 2

14. f(x) = -x^2 - 3x
g(x)= 6x^2
the problen is to find x that makes f =g: set the two functions equal to each other and solve for x:
-x^2 - 3x = 6x^2
Add x^2 to each side: -3x = 7x^2 then divide by x: -3=7x so:
x=-3/7

next we want to find f-g using the value of x:
(3/7)^2-9/7 - 6(3/7)^2 or -5(3/7)^2 -9/7
or -5(9)/49-9/7 = -45/49 -9/7 = - (45+63)/49 =108/49 = 2.204

Th other problems can be solved in the same manner

Answer 3

The language used in your question is of a non-standard nature to the best of my knowledge. I'm guessing the book wants you to find the set of values of x such that f(x) = g(x) which involves solving a quadratic equation. The other must mean find h(x) = f(x) - g(x) which is just a problem of combining like terms after subtracting g(x) from f(x).