Let's write the parametric line
(x,y,z) = (0,2,8) + t(5,-1,4)
(5,-1,4) is called the direction vector of the line. It's normal to the plane
5x - y + 4z = constant
We get the constant by substituting the point (3,0,7),
5x - y +4z = 5(3) - 0 + 4(7) = 43
5x - y +4z = 43
There's no if about it,

has a zero

so

is a factor. That's the special case of the Remainder Theorem; since

we'll get a remainder of zero when we divide

by

At this point we can just divide or we can try more little numbers in the function. It doesn't take too long to discover

too, so

is a factor too by the remainder theorem. I can find the third zero as well; but let's say that's out of range for most folks.
So far we have

where

is the zero we haven't guessed yet. Again we could divide

by

but just looking at the constant term we must have

so

We check

We usually talk about the zeros of a function and the roots of an equation; here we have a function

whose zeros are
X-2 is the answer hope this helps and I hope I’m not answering too late

Formula works when n=1
Assume the formula also works, when n=k.
Prove that the formula works, when n=k+1

Since the formula has been proven with n=1 and n=k+1, it is true. 
Answer:
0
Step-by-step explanation:
(f-g)(x) = 12-sqrt(x)
plugging in 144, we get 12 - 12 = 0
one could also do f(x)-g(x) which would yield 24-24=0