Answer:
-2
Step-by-step explanation:
Let's plug your functions f(x)=x^2-2x and g(x)=6x+4 into (f+g)(x)=0 and then solve your equation for x.
So (f+g)(x) means f(x)+g(x).
So (f+g)(x)=x^2+4x+4
Now we are solving (f+g)(x)=0 which means we are solve x^2+4x+4=0.
x^2+4x+4 is actually a perfect square and is equal to (x+2)^2.
So our equation is equivalent to solving (x+2)^2=0.
(x+2)^2=0 when x+2=0.
Subtracting 2 on both sides gives us x=-2.
Answer:
x=-2
Step-by-step explanation:
f(x) = x^2 - 2x
g(x) = 6x + 4
Add them together
f(x) = x^2 - 2x
g(x) = 6x + 4
-----------------------
f(x) + g(x) =x^2 +4x+4
We want to find when this equals 0
0 =x^2 +4x+4
Factor
What two numbers multiply together to give us 4 and add together to give us 4
2*2 =4
2+2=4
0=(x+2) (x+2)
Using the zero product property
x+2 =0 x+2=0
x+2-2=0-2
x=-2
